bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual differences in processing styles: validity of the Rational–Experiential Inventory
Authors: BJÖRKLUND FREDRIK , BÄCKSTRÖM MARTIN
Published: April 2008

In Study 1 (N= 203) the factor structure of a Swedish translation of Pacini and Epstein's Rational–Experiential Inventory (REI‐40) was investigated using confirmatory factor analysis. The hypothesized model with rationality and experientiality as orthogonal factors had satisfactory fit to the data, significantly better than alternative models (with two correlated factors or a single factor). Inclusion of “ability” and “favorability” subscales for rationality and experientiality increased fit further. It was concluded that the structural validity of the REI is adequate. In Study 2 (N= 72) the REI‐factors were shown to have theoretically meaningful correlations to other personality traits, indicating convergent and discriminant validity. Finally, scores on the rationality scale were negatively related to risky choice framing effects in Kahneman and Tversky's Asian disease task, indicating concurrent validity. On the basis of these findings it was concluded that the test has satisfactory psychometric properties.
Relational Aggression in Peer and Dating Relationships: Links to Psychological and Behavioral Adjustment
Authors: Ellis Wendy E. , Crooks Claire V. , Wolfe David A.
Published: April 2008

We examined the contribution of relational aggression in adolescents’ peer and dating relationships to their psychological and behavioral adjustment. In the Fall and again four months later, 1279 (646 female) grade 9 students reported on relational aggression perpetration and victimization in their romantic and peer relationships, depression/anxiety symptoms (psychological adjustment) and delinquency (behavioral adjustment). Using hierarchical regression analyses, controlling for Time 1 adjustment/behavior, peer relational aggression perpetration predicted depression/anxiety. Dating relational victimization also predicted depression/anxiety, but only for girls. Furthermore, girls who were perpetrators of relational aggression in both peer and dating contexts were most likely to show increases in delinquent behavior. We conclude that dating and peer relationships are not redundant, but make independent and additive contributions to adolescent adjustment. Girls, in particular, may be at greatest risk for poor outcomes when they have relationally aggressive relationships. Results also highlight the need for greater awareness of the complexity and significance of adolescent dating relationships.
Mothers' Cognitions about Children's Self‐control: Implications for Mothers' Responses to Children's Helplessness
Authors: Moorman Elizabeth A. , Pomerantz Eva M.
Published: April 2008

This research examined the role of mothers' cognitions about children's self‐control in their responses to children's helplessness. Mothers and their four‐year‐old children (N = 109) were asked to work on a difficult task in the laboratory. Mothers' hostility and warmth as well as children's helpless (vs. mastery) behavior were coded every minute. Mothers also completed a set of questionnaires assessing their cognitions about children's self‐control. Hierarchical linear modeling indicated variability among mothers in their minute‐to‐minute hostility, but not warmth, in response to children's helplessness. Mothers' cognitions contributed to this variability: The more mothers placed importance on, worried about, and believed they could influence their children's self‐control, the more hostility they demonstrated following their children's helplessness.
Eenvoudige mathode voor het interpreteeren van statistisch contröle‐materiaal
Authors: de Jong A. J.
Published: April 2008

A simplified method for the working out of statistical control data by means of a suitable abacus is described and explained. A practical example for a population corresponding to the Normal (Gaussian) Curve is given. This method can also be applied to Frequency Distributions not obeying the Law of Gauss, provided they can be represented by a known mathematical function.

A simplified method for the compilation of statistical data concerning weights by means of a balance provided with numerators, is described.

The possibility of the application of a system of numerators to automatic dosing machines is discussed, by means of which control, based on random sampling, could be replaced by weighing dosages individually.
Het begrip Universum in de Statistica
Authors: van Ettinger Ir J.
Published: April 2008

Summary  (The meaning of population in statistics).

The general opinion, that a population consists of a number of objects of observation is shown to be incorrect.

It is pointed out that a series of similar individual discriminations of observation has to be called a population.
De statistische kwaliteitscontrôle als economisch probleem (I)
Authors: Geiss Dr W.
Published: April 2008

Summary  (Statistical quality control as an economic problem I).

A discussion is given about the application of 100 inspection and inspection by sampling. The choice between these two methods has to be based upon economic principles.
Constructie van kansellipsen in een correlatiediagram
Authors: Hekker Ir Th.
Published: April 2008

Summary  (Construction of chance ellipses in a correlation diagram).

Chance ellipses in a correlation diagram are calculated from the formula of the normal correlation surface (the chance ellips P contains the area of the correlation diagram, where P% of the observations are found). The construction of these ellipses is explicated. A table with factors to construct the ellipses for different values of P is added.
De bewerking van veldproeven volgens de methode van Knut Vik
Authors: Stoffels Ir A.
Published: April 2008

Summary  (The treatment of field experiments by Knut Vik's method).

Agriculturists and statisticians have studied the problem, how to free the yields in a field experiment from the inequality of the soil. The method of the analysis of variance, due to the English statistician R. A. Fisher has taken an important place in the study of field experiments, so that other methods fell in the background.

The Norwegian agriculturist Knut Vik has suggested a method, which leads to good results without complicated calculations and without the knowledge of a great part of the mathematical statistics.

The mathematical foundation of this method is discussed in this article, which concludes, that the method of Knut Vik is of great importance for agriculturists, who don't want to perform intricate calculations.
Het quantitatieve verband tussen dosering en letaliteit bij proefdieren
Authors: Nass Drs C. A. G.
Published: April 2008

Summary  (On the quantal response of animals to drugs).

The methods of Bliss (6) and Fisher to deal with dosage mortality data were explained till the computation of the final regression line, which will be treated in a following article. These methods are based on the tacit assumption that the dosage mortality data do follow a constant probality distribution. This is not always true. In the cases of t.b.‐infected Cavias (7) and the convulsive effect of insuline to mice (4) the experiments are irreproducible and so a factor F must exist, which varies in an unknown and irregular way between the series. It is still possible then, to draw trustable inference relative to, say, two different preparations A and B of the drug, by mixing up the two series completely at random, safe for the difference between A and B. In this way F is degraded to an ordinary random variable and the analysis may be executed, as far as the difference goes, as if F were nonexistent.

The logarithmic distribution of the susceptibility to drugs may be taken as een instance of a wider rule, which embraces also the facts collected in the law of Weber—Fechner and ought to be called the Rule of Galton: In biology the logarithmic progressions are predominant to the arithmitic ones. That the logarithmic progressions are peculiarly obvious in the cases of susceptibility to drugs or to sensual stimuli, is due to the fact that here the range of variability is relatively large. Apparently the change of scales takes place at the very moment in which the physico‐physiologic frontier is trespassed. In the eye the current of action in the retina is closely proportionate to the logarithm of the physical magnitude of the light. According to Bliss (6) the adsorption in the tissues should be proportionate to the logarithm of the dose, rather than to the dose itself. It must however be said that the coincidences, shown by Bliss of log dosis‐probit‐curves, departing somewhat from normality, and suitably selected fragments of Langmuir‐sigmoids, are little convincing evidence for his views, because of the large flexibility of the sigmoids (3 parameters). The keen interest taken by Bliss in departures from normality of dosage mortality data is comparable to the interest taken in departure from normality at large in the childhood of biostatistics. It was seldom forgotten then, to compute the skewness and the kurtosis, or better still, to fit the best‐suiting Pearsonian curve, of any distribution. Much more seldom however, anything was done with the results. Nowadays the value of departures from normality is considerably depreciated. Significant departures from any normal or Pearsonian curve may always be shown, by taking enough observations, because not a single natural distribution can be exactly identical with one of those curves.
Een noodzakelijke correctie van de overschrijdingsgrenzen voor steekproefgemiddelden bij toepassing van stratified sampling
Authors: de Leeuw Th. A.
Published: April 2008

Summary  (A necessary correction of the control chart limits for averages of samples in the case of stratified sampling).

Application of stratified sampling results in smaller fluctuations of sampling than where the same total number of individuals is drawn at random from the superposed strata.

The proportion of the standard errors of the averages obtained by these two sampling methods may be expressed by a factor ϕ (o ≤ϕ≤ 1). The probability limits, between which the random sampling results would be fluctuating normally, should be corrected according to this factor.

A few properties of ϕ are discussed. This is graphically illustrated. Remarks have been added about the relation between the shape of the population of the sampling averages and the population from which the individuals are drawn, and about the difficulties which arise when the populations are non‐Gaussian.
Een statistisch problaem in de Klimatologie
Authors: Levert C.
Published: April 2008

Summary  (A statistical problem in Climatology).

The Climatological Section of the Royal Meteorological Institute of the Netherlands was asked to solve the following problem: Is the decrease in the quantity of precipitation along the eastern border of the Noord‐Oost‐polder of the Zuider‐Zee since reclamation in 1942, significant?

The data from the stations at Lemmer and Kampen have been statistically analysed. The results of this analysis may be interpreted as follows: if the change is a real one, it is overshadowed by the well known fluctuations of chance.

In the course of the computation two questions arose: speaking generally

when altered circumstances produce a certain change in the true value of the phenomenon, how many measurements have to be made in order to prove this change to be significant? and

being able to make only a certain number of measurements, what is the minimum real change in the phenomenon which can be proved to be significant?

The theory developed in this article and verified by numerical climatological data may well be generalised and may then be useful in other branches of applied science.
De omvang van de steekproef bij een enkelvoudig steekproefsysteem
Authors: Enters J. H.
Published: April 2008

Summary  (Sample size for a single sampling scheme).

The operating characteristic of a sampling scheme may be specified by the producers 1 in 20 risk point (p1), at which the probability of rejecting a batch is 0.05, and the consumers 1 in 20 risk point (p2) at which the probability of accepting a batch of that quality is also 0.05.

A nomogram is given (fig. 2) to determine for single sampling schemes and for given values of p1and p2the necessary sample size (n) and the allowable number of defectives in the sample (c).

The nomogram may reversedly be used to determine the producers and consumers 1 in 20 risk points for a given single sampling scheme.

The curves in this nomogram were computed from a table of percentage points of the χ2 distribution. For v > 30 Wilson and Hilferty's approximation to the χ2 distribution was used.
Over correlatierekening en de herleiding van klimatologische reeksen
Authors: Varangot V.
Published: April 2008

Summary  (A useful climatological application of regression theory) It is often required to estimate the 24th mean temperature from a few known temperatures, e.g. at 8h, 14h and 19h, when a sample of accurately known 24h means is available. The usual method is to add a constant to the mean of the three temperatures.

It is better however to compute a regression equation of the accurate 24h means on the three temperatures.

An example is given, showing that the efficiency of the regression method is about 6 times as great as that of the usual method.
Over de spreiding bij het droge‐stofonderzoek van brood
Authors: Burg L. v. d.
Published: April 2008

The accuracy of the determination of the amount of solids in bread.

Of a loaf with a nominal weight of 800 grams only about 480 grams remains after complete drying. This so‐called ‘amount of solids in bread’ is regularly checked by samples. From a batch of loaves a group of at least 5. but usually more, are taken at random and weighed. From this group one is selected with a weight as nearly as possible equalling the average weight of the whole group; for two slices of this sample loaf the decrease in weight upon drying is determined in the laboratory, and is considered as representative for the entire batch.

The accuracy of these determinations is analysed on the basis of 35 samples which were investigated in 3 different laboratories. The standard error is estimated at 5 grams per loaf. The influence of various factors, such as the method of sampling which may be altered in many ways, is briefly considered, while in a final section the results obtained are discussed from a practical point of view.
Het verbond tussen werkelijke verdeling, foutenverdeling en waarneem‐bare verdeling
Authors: Picard Drs H. C.
Published: April 2008

The relation between the true distribution, the error distribution and the observable distribution.

If ξ is a chance variable with a ‘true’ distribution function ξ (ξ), and if ϕ (x—ξ; ξ) represents the distribution of the errors made in observing ξ, than the actual observations will be distributed according to the ‘observable’ distribution which arises from a superposition of the true and the error distributions. By making use of moment generating functions, relations are derived between the fundamental parameters—mean, variance, β1 and β2—of the three distributions mentioned above, under the supposition that these functions are all continuous and differentiable, and that the error distribution is symmetric. When these assumptions do not hold similar methods may still be employed.

In the general case that the error distribution depends on ξ we arrive at equations (6) to (12), which, if this distribution is independent of ξ, simplify to equations (13) to (16); if the error distribution is normal these can be further reduced to (19) to (21), a set of equations already established by Sittig1)in a previous paper.

The same method of computation can be extended to cases of more than one dimension, and equations (23) to (27) express the relations between the variances and the correlation coefficients for a two‐dimensional distribution.
De evolutie van net gebit van de orang oetan vergeleken met de evolutie van het gebit van de mens
Authors: Hooijer Dr D. A.
Published: April 2008

The evolution of the dentition of the orang‐utan compared with the evolution of the human dentition.

From a comparison of the average robustnesses computed from a collection of 3170 prehistoric teeth with those observed in the teeth of 80 recent skulls it is concluded that the evolution of the dentition of Pongo pygmaeus follows behind the evolution of the human dentition along parallel lines. The data on which this conclusion has been based are set out in a Simpson diagram in fig 1 (with accompanying text in English).
Critiek op de “Hyperbolische Foutenwet”
Authors: Brethouwer D. H. G. , Hamaker H. C.
Published: April 2008

Criticisms against the ‘Hyperbolic Error Distribution’.

In a previous article in this journal (Vol. 1, p. 55, 1948) the hyperbolic error distribution

was derived by theoretical argument, starting from simple hypotheses. Against this derivation criticisms have been raised from various sides. These are answered in the present paper.

Though it is on the one hand acknowledged that an error has slipped into the previous arguments, it is on the other hand maintained that the hyperbolic distribution can be held upright on a slightly altered basis, namely on a set of approximate, instead of exact, equations.

In a postscript the editors point out that serious objections can be raised against these altered views.
Frequentieverdelingen en mengproblemen
Authors: de Jong A. J.
Published: April 2008

Frequency distributions and mixing problems.

If in packages of a powdered mixture a minimum quantity of some essential and expensive component has to be guaranteed, the degree of homogeneity of the mixture becomes an important industrial probIem. The greater the dispersion, the greater will be the overweight required in order to satisfy the prescribed minimum conditions. The problems which may arise under such conditions and the value of a study of the mixing process and its efficiency are briefly discussed. In essence they amount to a study of frequency distributions describing the properties of the mixture.
Enige aspecten van de spreiding van arbeidsprestaties*
Authors: de Jong J. R.
Published: April 2008

Some aspects of the spread observed in time studies.

In the introduction the importance of time studies in mass production is mentioned. Next figures 1, 2 and 3 give some examples of the frequency distributions observed for the time intervals required for cyclical factory operations. It is pointed out that for comparing different jobs the specific deviation, s/√t, is often more useful than the standard deviation, s, or the average time t̄. If greater detail is required a study of the historic sequency may be of advantage; this sometimes reveals marked periodicity in speed (fig. 5). If one cyclical operation is split up in a number of phases, the variance of the whole is often larger than the sum of the variances of th; components, wich demonstrates the existence of correlations. Sometimes the distribution of 1/t or of 1/t2 is found to be slcser to normal than that oft. In ajinal section the main causes of variation are briefly surveyed.
Het nut van waarshijnlijkheidspapier voor de variatiestatistiek*
Authors: Jr. G. van Iterson
Published: April 2008

The utility of probability paper in studying the statistics of biological variations.

This paper mainly deals with various applications and theorems concerning arithmetic probability paper.

It is pointed out that the so‐called ‘normal function’ introduced by Kapteyn and Van Uven [1,2] is the same function as that which would be obtained by plotting the corresponding distribution on arithmetic probability paper. For a normal distribution the ‘normal function’ is a straight line, for a logarithmiconormal distribution it is a logarithmic curve.

Galton's well‐known apparatus for demonstrating the genesis of a normal distribution (fig. 5) was modijied by Kapteyn (fig. 6) so as to produce a skew distribution. The latter apparatus can be transformed into the former by a process of stretching and compressing in a horizontal direction, and this transformation is again described by the ‘normal function’ of the non‐normal distribution shown in fig. 6.

If the dividing blocks in these apparatus are conceived infinitesimally small and all of equal height, the path of those grains of small shot which always fall towards the right, or always towards the left, is again the ‘normal function’, or its image with respect to a horizontal line.

Further some applications of probability paper in correlation studies and for the representation of certain laws of growth are discussed.

In ‘Appendix I’ a method for χ2‐testing the reliability of a normal distribution fitted by means of probability paper is described, white in ‘Appendix II’ a mathematical proof is given of a number of theorems that were merely enunciated in the main paper.
Rangcorrelatie en de schattingsproef van Varangot*
Authors: Hemelrijk J.
Published: April 2008

Rank correlation methods applied to an experiment on estimation of V. Varangot.

The results of an experiment on estimation described by V. Varangot [i] are analysed with the method described in M. G. Kendal V S, Rank correlation methods “under the title, The problem of m rankings”. The main advantage of this method is the possibility of applying a significance test to the result.
De centrale gedachte van de correlatierekening1
Authors: Tinbergen J.
Published: April 2008

The basic idea of correlation analysis

In his introduction to the four following papers on applications of correlation methods, Prof. Tinbergen presents correlation analysis as the means of establishing relationships between the factors involved, in those fields of natural and social sciences, where proper experimenting is impossible.

Prof. Tinbergen recommends that workers in different fields take cognizance of each other's results with applications of correlation analysis — hence this symposium. On the other hand, uncritical imitation of methods used succesfully in one field, e.g. biology, may lead to serious failure in another, e.g. economics.
Gebruik van correlatierekening voor het vaststellen van werktijden in het expeditiebedrijf
Authors: Sittig J.
Published: April 2008

The establishing of standards in the transport trade by correlation analysis

A firm of wholesale grocers have to deliver, once a week, goods to their clients according to their varying specifications. Delivery is effectuated by the firm's motor trucks.

Observations of standing and moving times were made by means of automatically recording instruments.

Standard time of delivery is given by the equation:

T = 2,29G + 10,64K + 1,82A + 19,11

T… standard time in minutes

G… total weight to deliver, in 100 kg

K… number of clients to visit

A… total distance to be covered, in km)
Gesuperponeerde normale distributes en splitsing in elementaire curven
Authors: van Alphen G. W. H. M.
Published: April 2008

The splitting up of heterogeneous distributions into two normal components

It is shown that the frequency distributions of the nucleus volumes in various areas of the human cerebral cortex may be adequately described by two normal distributions superimposed on each other. The two normal components of the frequency distributions are found graphically by means of previously prepared sets of normal frequency curves. Curves of one set have the same mean and standard deviation, curves belonging to different sets have different standard deviations. The curves of one set have areas ranging from 10% to 100%.
Grafische bepaling van de tweevoudige correlatiecoëfficiënt
Authors: Varangot V.
Published: April 2008

A nomograph is given for the multiple correlation coefficient defined by (I).
De natuur als tegenspeler*
Authors: van Dantzig D.
Published: April 2008

Playing Against Nature.

Human activity implies making decisions under partly unknown circumstances but backed by former experience.

Modern theories of mathematical statistics enable us in certain cases to determine among all decisions under consideration those which have the greatest chance to lead to a given end. This is achieved by considering human activity as a combined game of brains and chance, with “nature” as a fictitious opponent.

Though excessive mathematical difficulties are as a rule prohibitive for complete calculations, we nevertheless get a better idea of what the words “rational behaviour” stand for. In many cases, where a sufficient quantity of information in the form of statistical material is available, it is possible to arrive at concrete results. In particular this is the case when economic factors prevail; at the same time the statistical theory of testing hypotheses can be seen in a broader aspect.

This paper, read at the Meeting of the “Vereniging voor Statistiek” on March 6, 1925, gives an elementary exposition of some of the principles of Wald's theory of Decision Functions and Von Neumann and Morgenstern's Theory of Games and Economic Behaviour.
De toets van Wilcoxon
Authors: van der Vaart H. R. , van Dantzig D.
Published: April 2008

Two lectures on Wilcoxon's two sample test.

This is an account of two lectures on Wilcoxon's parameterfree two sample test, held by H.R. van der Vaart en Prof. D. van Dantzig, for the mathematical statistic's section of the „Vereniging voor Statistiek”. Van der Vaart discussed the results of his studies about the power function of the test for very small samples, comparing it with the power function of Student's test. These results have been published completely in [1]. Although Wilcoxon's test is far more general than Student's test, its power is only slightly less. Prof. Van Dantzig then discussed the consistency of the test, indicating an exhaustive class of alternative hypotheses for which the test is consistent. These results have been published in [2].
Enkele aspecten der mathematische statistiek1
Authors: Hemelrijk J.
Published: April 2008

Some aspects of mathematical statistics

Inaugural adress for the “Technische Hogeschool” at Delft on November 5th, 1952. The basic principles of mathematical statistics and the scope of its app icabidty to practical problems of various kinds are discussed on an elementary level. The method of obtaining an upper confidence limit for an unknown probability is treated from the frequentionist's point of view.
Statistiek in Amerika
Authors: ten Have O.
Published: April 2008

General impressions of one of the members of the Technical Assistance Team Nr 77 “Industrial Censuses” which visited the U.S. in the summer

of 1951.

In the U.S.A. are more statistical data available—especially in the field of industrial‐ and labourstatistics— than in most of the European countries. Statistical research is very advanced and there is money available for this research.

Some explanation is given for the fact‐mindedness and thestatistical‐mindedness of the American public as a whole.

A description is given of the decentralised computation of government‐statistics and the co‐ordinating task of the Bureau of the Budget.
De Internationale Statistische bijeenkomsten in India gehouden in December 1951
Authors: Hamaker H. C.
Published: April 2008

An account is given of the International Statistical Conferences, held in Indiaduring the month of December, 1951.
Methode van de kleinste kwadraten, toegepast op een stel simultane vergelijkingen die één of meer constanten gemeen hebben
Authors: van der Heiden J. A.
Published: April 2008

The application of the method of least squares to a set of simultaneous equations which have one or more constants in common can be simplified by combining the equations into one equation. This can be done by assigning suitable values to the variables.

This method has the advantages that it allows of giving the normal equationsa more regular form than that obtained by treating them separately, and that the usual formulae for the calculation of the best values of the constants and of the standard deviations can be applied without alterations.
Voorspelling en profetie
Authors: van Dantzig D.
Published: April 2008

Prediction and prophecy.

With the help of a number of mythological and scriptural examples the requirements are sketched, which a scientific prediction should meet. These requirements are:

(A) unambiguity, that is to say it must be as clear as possible under which observable circumstances the prediction is fulfilled and under which it is disproved;

(B) the prediction must rest on information consisting of preliminary observations;

(C) the accuracy of the prediction must be stated by the magnitude of the so‐called prediction interval and

(D) the reliability, i.e. the probability that the prediction will be fulfilled, must be mentioned.
Voorspellen van de economische toestand
Authors: Kuiken L. C.
Published: April 2008

Prediction in the economic sphere.

The technique of prognosis, as an aid in government policy, is of great importance for the general economic prosperity. A description is given of the method by which the Netherlands Central Planning Bureau, as advisor to the government, endeavours to compile an overall picture of the economic future. Further, information is furnished regarding applied aggregation, in which the micro‐economic magnitudes are combined into macro‐economic variables and the micro‐economic relationships into macro‐economic relationships. The optimum aggregation combines a still adequate wieldability with an acceptable error.

Part of the variables in the econometric model must be estimated independently. Generally speaking, the magnitudes can be classified into two categories: the autonomous and the non‐autonomous variables.

In addition, there is another important classification, viz. the division into: a. objects (e.g. employment, actual wage level), b. instruments (e.g. taxation, government expenditure), c. data (e.g. growth of population, world‐wide economic conditions), d. irrelevant variables (e.g. nominal wage level, price level).

Furthermore, Goudr***aan's criticism of the method for determining the economic structure is discussed, because he is of opinion that the approach to econometry has so far been incorrect in principle, both as regards the analysis of the historical time series and the technique of prognosis.
Voorspellen van landbouw‐opbrengsten
Authors: Ignatius J. G. W.
Published: April 2008

Prediction of harvests.

With respect to the prediction of harvests in agriculture a distinction can be made between short‐term estimates and actual long‐term predictions.

Harvest estimates are made by the Municipal Advisory Committees for Agricultural Statistics headed by the Burgomasters. These estimates are made either just before (provisional harvest estimate) or immediately after the harvest (definitive harvest estimate). During a considerable part of the year estimates are made with respect to the development and the expected harvest by personnel of the agricultural and horticultural information services, the state of the crops being expressed in a single figure.

Long‐term prediction of harvests are frequently based on relationships between the weather factors and the yields. In the Netherlands some investigations have been carried out in this connection by members of the Royal Netherlands Meteorological Institute and of the agricultural and horticultural information services.

Predictions with respect to the development of the livestock position, particularly pigs, are altogether of a different nature. Such predictions are made on the strength of monthly data regarding the number of female animals covered, which information is obtained by means of random tests.

Predictions are also made in the fisheries industry, particularly with respect to the herring catches landed.
Samenvatting
Authors: Idenburg J.
Published: April 2008

Recapitulation.

The general views, held in common by several of the previous nine speakers on the sixth Statistical Day of the Netherlands Statistical Society, have been summarized. The (implicit) assumptions, common to all predictions, whether of the qualitative (non‐measuring) or of the quantitative (measuring) kind, are regularity and causal connection between phenomena. Moreover, all predictions are subject to certain conditions, which, for the “measuring” ones, have to be put into quantitative terms.

In all domains of social life the measuring rod is making headway into realms in which it did not enter previously, and prediction is no exception to the rule. Nevertheless, this process cannot proceed beyond certain fundamental limits, guarding perhaps the most precious elements of life.

In the meantime we have to further prediction in the indicated direction, not in the least because of its use in planning, the active counterpart of prediction.

May it be to the benefit of mankind.
Overzicht van de ontwikkeling der visserijtheorie
Authors: Westenberg J.
Published: April 2008

Survey of the development of the fisheries theory

A concise review is given of theoretical developments concerning the problem of overfishing. Preliminary concepts have evolved in the course of time. Management is now considered in terms of fishing activity and mesh size on a complementary basis. A special series of combinations of these is given preference on biological grounds. Economic factors play part in the final stage of designing fishery regulations.
Omzetting van een in gehele graden Fahrenheit gegeven frequentieverdeling in een, welke een klassebreedte van een graad Celsius heeft
Authors: Heyna B.
Published: April 2008

Transformation of a frequency distribution

A method is described to convert a frequency distribution in which the frequencies are given for each whole degree Fahrenheit, into a frequency distribution with class intervals of one degree centigrade in such a way, that the resulting distribution has no “unreal peaks”, which are introduced by the transformation.
Richtlijnen voor de berekening van productie‐indices
Authors: Vos J. W. E.
Published: April 2008

On methods of computation of index‐numbers of industrial production.

When computing production‐index‐numbers at least three different weighting systems are available:

1. man‐hours expended per unit; 2. value added per unit; 3. prices.

According to the different aims for which production indices are to be used different weighting procedures should be applied, from which it follows that there is no unique index‐number, satisfying all conditions that may be enforced on them. If it is the aim to construct an index‐number of productivity of labour, it is shown that weighting with man‐hours is to be carried out. If however the aim is to have an index of the economic activity of industry, weighting with value added should be applied. In general, both man‐hours and value added are unknown for the separate products of one group of factories. Weighting with prices is therefore the only possible alternative.

Finally the construction of an index of net industrial production, that is production minus the consumption of raw materials, is considered. It is shown that weighting of the net production by value added leads to weighting with prices of all production‐ and consumption‐items, quantities of the latter thereby counting negative.
Dupliceerbaarheid en reproduceerbaarheid van waarnemingen
Authors: Heiden J. A. v. d.
Published: April 2008

This paper deals with the formulae, which make possible the calculation of quantities indicating accuracy, defined as follows and used in the “Koninklijke/Shell Laboratorium, Amsterdam”.

The repeatability r represents the greatest difference between two single results that should be considered acceptable if they are obtained within a small interval of time by a competent operator using his set of apparatus in one laboratory.

The reproducibility R(n) represents the largest acceptable difference between the mean of the nA results of a laboratory and the mean of the nB results of another laboratory, possibly obtained at widely different times (n=nA+nB/2).
De theoretische zijde van de methode der kleinste kwadraten
Authors: van Ijzeren J.
Published: April 2008

The theoretical aspect of least squares.

This article contains a slightly modified presentation of the Markoff theory of least squares as developed along different lines by Aitken and by David and Neyman. The modifications aim at a more complete treatment and a geometrical illustration of the connection between best linear estimates and generalized least squares. The unbiasedness of ordinary least squares estimates in the case of heteroscedastic and correlated errors is stressed and the loss of efficiency is shown to be generally small. Topics like orthogonalization, partial correlation and what is called “over‐correlation” are treated in passing.

Matrices are constantly used, being the adequate tools in this matter. In the appendix a special relevant matrix theorem is derived, viz. a generalization of the well known Cauchy inequality.
Statistische oplossing van een passingsprobleem
Authors: Landman H. J.
Published: April 2008

The clearance between bearing and bore depends more or less on the form (out of round) of the bore.

Consequently, if high accuracy is required and a positive clearance must be sure, the information got from measuring a turned bore must contain a clear indication about the value of its minimum diameter.

A statistical solution is given to find the distribution of the minimum diameter, if known:

the smallest allowable clearance,

the distribution of the outside diameter of the bearing,

the standard deviation of the minimum diameter of the bore.

Moreover the measuring method at the lathe was revised and a control chart for the median was introduced.
The effect of rounding off in samples
Authors: Wise M. E.
Published: April 2008

Samenvatting

Dit artikel bevat een elementaire behandeling van afrondingseffecten in steekproeven.

Zoals men verwacht, neemt de variantie van het steekproefgermddelde door af ronding der waarnemingen toe met een factor 1 +b2/12σx2, waarbij b het afrondings‐ interval enσx2de stamvariantie is, in analogie met de bekende correcties van Sheppard. Verder wordt het effect van afronding op de variantie van de steek‐proefvariantie onderzocht. Er wordt op gewezen, dat de afrondingsfout ε in één steekproef gecorreleerd is met de afwijking van de nauwkeurige — d.w.z. niet afgeronde — stochastische variabele x van zijn gemiddelde μ, hoewel deze correlatie gemiddeld nul is. Het gevolg is, dat de variantie van de steekproefvariantie toeneemt. Bij “gewone” waarschijnlijkheidsverdelingen, die continue naar nul gaan bij x →, is deze toename gelijk aan

1/n(1/3b2σx2+ 1/180b4)

waarbij n de grootte van de steekproef is. Bij normale verdelingen is het effect ongeveer twee maal zo groot als de toename volgens de Sheppard's correctie van de afgeronde variantie.
Het voorspellen van levertijden uit gegevens over de voort‐gang van een project
Authors: Muller H. L.
Published: April 2008

Estimation of dates of delivery by extrapolation of progress‐data for a project.

The problem can be put in mathematical form with the aid of some assumptions with regard to the occurrence of interruptions.

The progress of the project is supposed to be interrupted by time‐intervals during which progress is fully stopped. These intervals start at irregularly distributed moments and have a variable size. The points on the time axis corresponding with the moments of stagnation will show a constant average density, if a constant average production capacity or development capacity is available. This means that the results are valid only if no alterations are made which influence the general progress of the project involved.

The application of probability theory to problems connected with promises of delivery may, in general, look unacceptable.

Many projects, however, have an experimental character and unforeseen technical and organisational troubles are unavoidable.

In such cases the theory makes it possible to obtain a maximum amount of information contained in the progress‐data and may help management to make the best decisions.
Statistische aspecten der muziek
Authors: Yntema L.
Published: April 2008

Statistical aspects of music

With reference to a recent paper in »Statistica« the problem of characterizing composers and their musical compositions by means of frequency distributions is approached from a slightly different angle. Not only the frequency of notes is considered, but also their duration. A method for representing this resulting weighted frequency‐distribution in a polar‐coordinate diagram is indicated and illustrated by means of some examples. It is demonstrated that in this way an analysis may contribute towards a better understanding of the structure of the various types of musical achievements.
Tien jaar wiskundige statistiek *
Authors: van Dantzig D.
Published: April 2008

The development of mathematical statistics during the last ten years.

Due mainly to the stimulating influence of the rapid development of mathematical statistics in England and the U.S.A. during and just after the war, the amount of work in the Netherlands in this field has been much greater and on a higher international level than before the war. A more favourable atmosphere for application of mathematical statistics has been growing. Education of young statisticians and, to a certain extent, statistical research have been promoted by the institution of chairs of mathematical statistics at several Dutch Universities. However, an insufficient number of young people are willing to devote themselves to fundamental research work, and too many of them are absorbed by industry. If this will not change within the next few years, it will hardly be possible to maintain the present level of mathematical statistical work.
Openingswoord van de Voorzitter 1)
Authors: de Jong A. J.
Published: April 2008

Inaugural speech.

Industrial statistics had their origin in Germany, where in the 1920s Daeves published a large number of papers on this subject.

A short time afterwards statistical work in the field of electrical engineering was started in America. It resulted in numerous articles in the Bell System Technical Journal, and in 1931 culminated in the publication of Shewhart's classical work.

An early publication in the Netherlands is the report submitted by van Ettinger during the “Efficiency days” in 1930, while in 1954 Schaafsma and Willemze published the first Netherlands standard work on quality control.
De statistische basis van de planning in een machinefabriek
Authors: Sittig J.
Published: April 2008

The normal or jigsaw‐puzzle method of planning cannot be applied to the production of an engine factory. One has to fall back upon a kind of statistical automatism, like in the planning of road traffic as opposed to the planning of railway traffic.

In order to do this kind of planning efficiently, it is necessary to know the statistical relationships between the degree of occupation (number of working hours divided by number of available hours) of the machines, the waiting time and the velocity of flow through the factory.

The statistical analysis of some of these quantities in an Amsterdam plant, manufacturing medium size diesel engines, showed that Erlang's formulas of waiting time in telephone traffic (with exponential distribution of holding times) are applicable.

These formulas are used to prove that the highest degree of occupation is not the best one from an economic point of view. Formulas and graphs are given for finding the optimum degree of occupation in engine factories and other works where the same conditions apply.
Het oordeel van een bedrijfsleider over de toepassing van de statistiek in het bedrijf
Authors: Meijs L. Th. J.
Published: April 2008

A manager's view on the application of statistics in the concern.

To be able to judge of the correct dosing of statistical methods in his concern a manager should discriminate between incidental research and systemetical application of statistics. A sound job limitation and good information are indispensable to the success of a statistical check system.

The cost of the introduction of statistical check methods into a concern with a variated manufacturing programme in the field of electrical engineering (350 people) was estimated to be Djls 18,000 in one year. In the next year more than this amount will be earned back through the savings and the improvements obtained.
Keus en kans in de theorie der economische politiek*
Authors: Tinbergen J.
Published: April 2008

Choice and chance in the theory of economic policy.

In this brief lecture “choice” refers to the aims of economic policy as well as to the instruments to be used. From this choice can be derived — as far as the relation between the economic parameters is known or postulated — the numerical value to be allotted to the free parameters (instruments of economic policy). “Chance” presents itself in different kinds of deviations which may occur between the calculated and the realised values of the economic phenomena.
Steekproeven bij administratieve contrôle *
Authors: de Wolff P.
Published: April 2008

The application of sampling in auditing.

A sampling procedure is developped for the application in audit‐procedures of a very large number of entries. The procedures can only be applied in cases where fraud will lead to a booking of an entry at a too high amount; it consists of the following steps:

1. to check all bookings, surpassing an amount of x0

2. to take a sample of the other bookings, and to check the items of the sample. The size of the sample and the amount x0 have been chosen in such a way that, in case no fraud has been detected, the maximum amount of fraud committed does not — with a predetermined confidence coefficient — surpass a likewise predetermined amount.
Ondernemer ‐ Marktonderzoek ‐ Consument*)
Authors: Bakker A.
Published: April 2008

Market research renders its services to all functions of marketing. Marketing implies integration of all functions in moving any type of goods or services from production to the final user.

Examples of problems related to the marketing functions, which can be solved by research, are given.

The author says it is a common misunderstanding that market research should always and solely mean the carrying out of field surveys. Remarkable results, however, can already be achieved by a statistical analysis of the company's own sales records and of ready‐to‐use external statistical information.

The producer who produces for stock and who sells via distributors is interested in an exact knowledge of the needs and the desires of consumers, and of their habits as regards buying and using the product. The sample survey brings him in direct contact with the final consumer.

An example of a method of sequential analysis is given. A considerable economy of costs and time can be obtained in this way.

The author concludes by indicating that market research is a staff‐function in the enterprise, and that analysis, interpretation and presentation of the survey‐results, ask for the utmost care in order to obtain maximum results of the research performed.
Statistiek en experiment*
Authors: Hamaker H. C.
Published: April 2008

Statistics and Experiments

After a brief survey of the general importance of the statistical design of experiments, two particular examples are discussed in detail, one dealing with a series of 7 simple experiments on the proper conditions for the production of swaged joints, the other being a 3 × 3 × 3 design on emission in radiovalves. These examples provide illustrative material for some problems of a general nature, to which little attention is paid in textbooks on the subject. Often more factors are mentioned than can be conveniently incorporated in a single experiment. One of the secrets of succesful experimentation lies in making a proper choice of those factors which should go into an experiment. Where experimentation is easy and rapid a series of simple two — or three — factor experiments is better than one complex design. Analysis of variance is not always needed; frequently too the data resulting from an experiment indicate that text‐book methods of analysis do not apply and the statistician or experimenter should be trained in recognizing such situations and in dealing with them. The paper ends with some general conclusions concerning the present and future status of statistics as an integral part of experimental science.