bluuebunny/crossref_metadata_2025 huggingface dataset:
Kwaliteitsnormen
Authors: Wijtenburg J. M.
Published: April 2008

In most cases the buyer of durable consumers' goods cannot judge of the essential consumption characteristics, and is consequently guided by the finish.

The manufacturer should bear this in mind, and should pay much attention to the outward appearance of these articles.

Quality control is difficult to realise here, since in most cases the relevant properties cannot be measured because of their most subjective character.

By means of a case study (bath‐tubs) the author illustrates the measures which had to be taken to effectuate quality control, and he mentions the results and successes yielded.
Statistische beschouwingen in verband met textiel
Authors: van Af Ir J. W.
Published: April 2008

Owing to the variability of the raw material and the large number of production units in textile industry the application of statistical methods is indispensable to obtain a high quality product.

The author discusses examples of the statistical problems cropping up in various phases of the production process.
Operational Research — managers beslissen met behulp van de wetenschap *
Authors: Sittig J.
Published: April 2008

This paper is an introduction to six short lectures about the theme “choice and chance”, implicated in different fields of human activity. It throws some light on the history, the methods and the importance of Operations Research. Attention is paid to the elements of the way which leads from putting the problem to taking the decision. A general illustration is given by means of a simplified example. Some remarks are made about post‐war development, task and future of O.R.
Het probleem van de ruïnering der spelers
Authors: Meinesz M.
Published: April 2008

The gambler's ruin.

When a single trial has two possible outcomes A and B, with probabilities p and q(p+q= 1), a succession of these trials forms a so‐called Bernoulli chain. The well‐known result for the probability of n times A and m times B is

In this article we consider the ruin problem, in which the initial capitals of the gamblers are a and b, respectively. In stead of a Bernoulli chain we then have a Markoff chain, with coefficients that are less simple than the ordinary binomial coefficients.

A more general expression (formula 1) is obtained for the probability distribution of the gambler's profit after a certain number of games, provided none of them became ruined beforehand. The probability for ruin after a certain number of games is a special case, similar to the results of Lagrange, Laplace and others, but appears in a form, more suitable for numerical calculations.

Some other results, obtained through the same method as developed in this paper are indicated.
Betrouwbaarheidsintervallen voor de spreiding van een normale verdeling bepaald uit het gemiddelde van een aantal steekproefbreedtes1
Authors: Klerk‐Grobben Gerda , Sandberg Jkvr. H. D.
Published: April 2008

Confidence regions for the standard deviation of a normally distributed variate based on the mean range of a number of samples.

The mean range of a number of small samples from normal populations with the same standard deviation a is often used to derive point‐ and interval estimates of this parameter. This paper provides tables which facilitate the computation of interval estimates and considers the problem, how many samples of size 5 or 7 must be used in order to attain a given accuracy in the estimation. Starting from
Verdelingsvrije toetsen voor twee steekproeven en de methode der 2 × 2 ‐tabel*
Authors: van Eeden Constance
Published: April 2008

Distributionfree two sample tests and the method of the 2 × 2 ‐ table.

The method of the 2 × 2 ‐ table may be used for testing the hypothesis that two probabilities pAand pBare equal. This test is based on two independent series A and B of independent trials, each trial resulting in a success or a failure with probabilities pAandqA= 1—pAfor series A, pBandqB= 1—pBfor series B.

Each of these trials may be considered as an observation of a random variable which may take the two values“: success and failure, which may be denoted by two symbols e.g. z1and z2.Then the two series A and B are two independent series of observations of two random variablesx(for A) andy(for B), taking the value z1,with probability pA(respectively pB)and the value z2with probabilityqA(respectivelyqB).The hypothesis pA=pBis then identical with the hypothesis thatxandypossess the same probability distribution. This hypothesis may be tested by means of a distributionfree two sample test.

A class of distributionfree two sample tests mentioned in[1] (cf. p.251)is considered. It contains i.a. the tests of E. J. G. Pitman, F. Wilcoxon, M. E. Terry and B. L. van der Waerden. In this mainly expository paper it is shown that each test belonging to this class, when applied to the series of observations mentioned above, is identical with the method of the2 × 2 ‐table.
The frequency of industrial accidents
Authors: Thomissen F. X.
Published: April 2008

Samenvatting

In aansluiting aan een artikel van B. A. Maguire, E. S. Pearsonen A. H. A. Wynn (1951), waarin een theorie wordt ontwikkeld betreffende de verdeling van de tussen twee op elkaar volgende ongevallen verlopende tijdsduur, wordt in het onderstaande een methode gegeven voor het bestuderen van de verdeling der tijdsintervallen tussen twee ongevallen bij variërende personeelsterkte.

Als resultaat van deze aanvulling is het nu mogelijk om voor verschillende bedrijven — c.q. voor eenzelfde bedrijf in verschillende perioden — de hypothese omtrent gelijke — c.q. gelijkblijvende — afhankelijkheid tussen tijdsintervallen en personeelsterkte te toetsen.
Enige Rangcorrelatieschema's*
Authors: van Elteren Ph. , Peype W. F. van
Published: April 2008

In this paper the following rank correlation methods are discussed especially with respect to their application to psychological research:

1. The method of m rankings (section 2),

2. Kendall's method of paired comparisons (section 3),

3. Durbin's method for balanced incomplete block designs (section 4),

4. A test for concordance in a particular incomplete design (section 5).

For the last case the distribution of the test statistic under the hypothesis tested has been investigated using the results of a sampling experiment. Mean and variance of this distribution are derived in an appendix by H. Kesten and J. Th. Runnenburg.
On the distribution of the test statistics of Kendall and Wilcoxon's two sample test when ties are present
Authors: Smid L J.
Published: April 2008

Samenvatting

Zoals bekend is, kan de exacte verdeling van de toetsingsgrootheid van Kendall voor rangcorrelatie als er geen gelijke waarnemingen optreden en ah de nulhypothese juist is, berekend worden met behulp van een recurrente formule. Hetzelfde geldt voor de toetsingsgrootheid van Wilcoxon voor het geval van twee steekproeven. Wanneer er wél gelijke waarnemingen optreden, kan men, zoals hier wordt aangetoond, een gegeneraliseerde recursieformule gebruiken. De berekeningsmethode, die berust op het herhaald toepassen van deze recursieformule, is minder afschrikwekkend dan die welke bestaat in het opstellen van alle mogelijke schema's en de berekening van de bijbehorende kansen.
De invloed van de keuze der gewichten op de hoogte van een gewogen indexcijfer
Authors: de Wolff P.
Published: April 2008

The influence of the choice of the weights on the value of an indexnumber.

Price and quantity indexnumbers are weighted averages of groups of price and quantity ratios and they are convenient instruments to indicate the general tendency of such groups, especially if the number of basic ratios is considerable. The frequent use of indexnumbers is due to the fact that they can often be applied to problems for which, strictly speaking, an indexnumber had to be used derived from the same group of ratios but based on a different set of weights.

Two typical examples of such problems are given.

The use of a set of weights differing from the appropriate one is only justified, however, when the indexnumber is rather insensitive to changes in the set of weights. A simple formula is derived showing that the relative change of an index‐number due to a change in the set of weights is equal to the product of the (weighted) coefficient of variation of the basic ratios, the (weighted) standard deviation of the relative changes of the weights and the (weighted) coefficient of correlation of the ratios and of the relative changes. The system of weights used in the calculation of these three factors is the same and is equal to the set of true weights belonging to the problem under consideration.

The practical use of the formula is demonstrated at the problem of index‐numbers of costs frequently encountered in the practice of cost accounting.
Opmerkingen over de standaardafwijking van de constante term bij regressie‐analyse
Authors: van Eijk C. J. , Moerman H.
Published: April 2008

Some remarks on the standard error of the constant term in regression analysis.

In this article a formula for the standard error of the intercept — when applying least squares — is derived for the case of two explanatory variables. This is done without using matrix algebra. The result is compared with the corresponding formula in matrix algebra, after which a design for computation is indicated.
Problems of Media Research: The Readership Survey of the Institute of Practitioners in Advertising*
Authors: Abrams M. A.
Published: April 2008

Gedurende 1956 werd door het Institute of Practitioners in Advertising een onderzoek ingesteld naar het lezen van nieuwsbladen en tijdschriften in Engeland. Met behulp van een steekproef werd van 16000 personen boven de 15 jaar ter zake de gewenste informatie verkregen.

Om practische redenen werd een stratijicatie toegepast op basis van socio‐economische factoren: de namen van de te ondervragen personen werden ontleend aan de verkiezingsregisters.

Bij het interview werd een fotografie van de volledige titel van elk blad getoond. Teneinde systematische afwijkingen van het geheugen door vermoeidheid als gevolg van het interview te elimineren, werden 96 verschillende volgorden van de bladen toegepast: dit roteren bleek van grote invloed op de antwoorden te zijn.

De gemiddelde Britse volwassene leest elke dag twee nieuwsbladen, (op Zondag minstens twee), voorts drie weekbladen en één maandblad.
Recente resultaten op het terrein van economische voorspellingen op korte termijn *)
Authors: Theil H.
Published: April 2008

In recent years a remarkable development is shown in the, field of ecomomic forecasting. Specially this holds with regard to the “Central Economic Plans”, the investment polls and the Business Test.

In the latter “test” the managers of enterprises themselves are forecasting their own future activities and certain external factors. This paper contains some reflections about the merits as well as the deficiencies of these forecasts.
The occurrence of “twin” storms from the North West on the Dutch coast
Authors: Rijkoort P. J. , Hemelrijk J.
Published: April 2008

Samenvatting

Het optreden van “tweelingstormen” aan de Nederlandse kust.

Enige dagen voor Kerstmis 1954 volgden twee vrij zware stormen dicht op elkaar (21 en 23 December). Dit deed de vraag rijzen of wellicht zulke “tweelingstormen” vaker voorkomen dan te rijmen volt met een aselecte verdeling van stormen over de dagen van een jaar. Bij een dergelijk onderzoek — hier gebaseerd op windsnelheden gemeten in den Helder van 1904—1944 en van 1945—1953—dient rekening gehouden te worden met seizoeneffecten. De “jaarlijkse gang” der stormfrequentie werd onderzocht en een sinus‐vormige kromme werd aangepast (fig. 3). De waargenomen en de theoretisch verwachte frequentie — de laatste onder de hypothese van aselectheid — van de tijdsintervallen tussen op elkaar volgende stormen werden berekend en uitgezet in fig. 2. Een toets, gebaseerd op combinatie van 2 × 2‐tabellen, werd toegepast om deze hypothese te toetsen.

Daarbij bleek, dat tweeling‐stormen inderdaad vaker voorkomen dan op grond van aselecte verdeling der stormen te verwachten is en wel ongeveer twee a drie maal zo vaak. De kans op een storm is twee en drie dagen na een storm groter dan anders. Dit feit kan van belang zijn voor de keuze van de hoogte van zee‐dijken. Een meteorologische verklaring van dit verschijnsel wordt te dezer plaatse niet gegeven.
Open plaatsen in orthogonale proefschema's
Authors: Storch J. M.
Published: April 2008

There are different methods to analyse an orthogonal scheme of experimental numbers, showing some missing plots. In this paper it is shown by a simple illustrative example how such an analysis can be made. Some rules for diflerent cases are given, together with some derivations of the precepts used.
Practische [berekening van de standaardafwijking van de constante term bij regressie‐analyse
Authors: van Ijzeren J.
Published: April 2008

The formula arrived at in a previous article [1] is adapted to the usual computation schemes of regression analysis.
Enige statistische aspecten van de factoranalyse*
Authors: de Leve G.
Published: April 2008

In this report attention is paid to the hypotheses of Factor Analysis. The author makes a distinction between Component Analysis and Factor Analysis. Some statistical objectives of Factor Analysis are formulated and a summary of some known statistical techniques of Factor Analysis is given.
De taak van de Medische Statistiek*
Authors: Rümke L
Published: April 2008

The task of medical statistics.

After stressing the ethicaf necessity that efficient use be made of data obtained from experiments on human beings, examples are given of the application of statistical methods in some medical experiments. The statistician can help the research worker not only in applying tests of significance, but also in making the design of an experiment. The possible development of medical statistics at the Dutch universities in the coming years is described.

Mijne Heren Directeuren der Vereniging voor Hoger Onderwijs op Gereformeerden Grondslag, Mijne Heren Curatoren van de Vrije Universiteit, Dames en Heren Hoogleraren, Lectoren en Docenten, Dames en Heren leden van de Wetenschappelijke Staf, Dames en Heren Studenten, en voorts gij allen, die deze plechtigheid met uw tegenwoordigheid vereert, zeer gewaardeerde toehoorderessen en toehoorders,
The Efficiency of Some Distribution‐Free Tests
Authors: Noether Gottfried E.
Published: April 2008

Samenvatting

Laten T1 en T2 twee toetsen zijn voor dezelfde hypothese θ=θ0betreffende de waarde van een parameter θ, Zij verder de onbetrouwbaarheidsdrempel van beide toetsen gelijk aan α en het onderscheidingsvermogen tegen de alternatieve hypothese θ=θ1 geliik aan 1‐β. Indien toets T1 nu n1 waarnemingen vergt en toets T2n2 waarnemingen, dan wordt de relatieve doeltreffendheid (Eng.: efficiency) van toets T1 ten opzichte van toets T2 (als toetsen voor θ=θ0 tegen θ=θ1 gegeven door: e = n2/n1. Indien men de waarde van θ1 op een bepaalde wijze naar θ0 laat convergeren bij toenemende n1, is het in vele gevallen, door gebruik te maken van een stelling van α en β Deze limiet‐waarde wordt de asymptotische relatieve doeltreffendheid (volgens Pitman) genoemd. In dit artikel wordt een overzicht gegeven van hetgeen bekend is over de asymptotische relatieve doeltreffendheid van een aantal verdelingsvrije toetsen ten opzichte van de corresponderende standaardtoetsen.

De conclusie van de schrijver is, dat men bij het gebruik van verdelingsvrije methoden met een hoge doeltreffendheid (bijv. de symmetrietoets en de twee‐steek‐proeven‐toets van Wilcoxon, de toets van Kruskal voor k steekproeven en de methode van m rangschikkingen) slechts zeer weinig informatie kan verliezen en dat zelfs het gebruik van minder doeltreffende verdelingsvrije methoden gerechtvaardigd kan zijn.
Prijsverwachtingen volgens enquêtes onder consumenten*
Authors: Lange H. , Kaptein E.
Published: April 2008

Price expectations based on consumers pollings

The authors consider the influence of price expectations on savings and the purchases of durable consumers goods. These expectations, based on monthly pollings of the Dutch Gallup Institute (N.I.P.O.), are “explained” by relating them to the price movements in the past. Their quality is judged by comparing them with the actual price changes. The conclusion is drawn that the price expectations contain, in the period considered, more information about the future than could be obtained by means of a mere extrapolation of the price movements in the past.
Scheefheidstoetsen*
Authors: van de Panne C. , Lange H.
Published: April 2008

Testing against skewness.

This note deals with the skewness coefficient based on quartiles [defined in (1.3), M being the median and QL and Qv the lower and upper quartile respectively], and considers its distribution over the set of random samples drawn from normal and rectangular parents. The asymptotic sampling variance is derived [(2.1) jor a normal, (2.2) for a rectangular parent, n being the sample size], after which the hypothesis is tested that S is normally distributed with zero mean and a variance which equals its asymptotic value. The evidence, based on 400 samples of normal and rectangular numbers of various size, suggests that this null hypothesis need not be rejected.
Het optimaliseren van vertakte bemonsteringsschema's
Authors: Veen B.
Published: April 2008

Optimum allocation in nested sampling.

A problem of optimum allocation in nested sampling is considered [1, 2, 3]. In practice it turned out that, though considerable savings could be realized, the known formulae often do not sufficiently approximate the true optimum sample numbers. This is the case where small samples, unfavourable ratios of costs and variances, or designs with more than two classifications, are concerned. The departures are caused by the discrete character of the problem, whereas the formulae hold for continuous cases.

A method for optimum allocation, which takes the discrete character of sample numbers into account, is given together with an example of its application.
Het statistische verband tussen arbeidsproduktiviteit en produktie
Authors: Barten A. P.
Published: April 2008

The statistical relation between labour‐productivity and production.

Rising labour productivity can be induced by increases in output, or result from “autonomous” factors. Many induced increases will be irreversible, in particular those associated with “learning” processes. Under conditions of continuous economic growth the learning curve hypothesis leads to a simple exponential relation between labour demand and output in the long run.

In the short run, current and past profits and the profitability of import substitution join output as explanatory factors of labour demand.

In the long run, the effect of growth of capital must be taken into account. Autonomous factors can be represented by an exponential trend. With United States data, increasing returns to scale are still found. Under conditions of a constant savings ratio and continuous population growth a production function, which takes account of all these factors, can be shown to be compatible with a constant labour‐output elasticity, however.
Wat doen wij in een bedrijf met statistiek?*
Authors: Root W. J.
Published: April 2008

How to apply business‐statistics?

For the use of statistics in business an adequate organization and a good understanding are necessary. Specialists must only give advices. The management must create the climate for a good co‐operation. Some examples are given whereby statistics are applied succesfully.
Efficiënte gewichtscontrole van pakjes margarine*
Authors: Doornbos R.
Published: April 2008

Efficient weight control of margarine packets.

A process is described where the classical control charts on average and range of five successive packets cannot be applied because it is not under control. By taking four packets and recording their total weight at a single weighing the control is improved and the labour reduced.
Omvang chauffeursploeg en rijtijdenbesluit*
Authors: van Maare J.
Published: April 2008

The numerical size of a shift of drivers and their time limitations in carrying out their duties.

In order to acquire the fullest employment of a shift of drivers, two important factors must be taken into account:

1. The customer must obtain his orders in time, as frequently as possible.

2. The chances to infringe the law, which determines the time a driver is allowed to work, must be known and small within reason.

In this essay is indicated how it is possible, in a particular situation to find a way out. This resolution has been attained by scrutinizing the planning, which was applied in the past. This way out, however, is only possible under certain conditions.
On X2‐ tests for contingency tables of negative multinomial types
Authors: Steyn H. S.
Published: April 2008

Samenvatting

Om te toets of die twee kenmerke waarvolgens die frekwensies in 'n gebeurlikseidstabel opgestel is onafhanklik is, word gewoonlik 'n X2 toets gebruik. In die opstelling van so 'n toets word die totale frekwensie as vas beskou. In hierdie artikel word aangetoon hoe 'n X2‐toets nog gebruik kan word wanneer die steekproefneming voortgesit word totdat 'n vooraf vasgestelde frekwensie in een selbereik word. Die totale frekwensie is dan 'n stogastiese veranderlike. Die eienskappe van die randverdelings van 'n negatiewe multinomiaalverdeling word gebruik om die parameters wat in die X2‐verdeling optree te skat.
Statistische methoden voor het aanwijzen van uitbijters
Authors: Doornbos R.
Published: April 2008

Statistical methods for the rejection of outlying observations.

The principles are given of a class of slippage tests. Applications are discussed for the case of a sample from a normal distribution, for the Poisson‐case, for the method of m rankings and for the distributionfree k‐sample case.
Certainty about Uncertainty
Authors: KENDALL M. G.
Published: April 2008

“Nothing is more uncertain than the length of a given human life; nothing is more certain than the solvency of a life assurance company”.
Uncertainty in measurement and control
Authors: VAN DER GRINTEN P. M. E. M.
Published: April 2008

Summary Controlling is intervening in a situation on the basis of measurements. The three elements occurring in this definition may each contain an uncertainty that sets a limit to the control efficiency:

Themeasurementsmay be in error owing to both inaccuracies and sluggishness of the measurements. Proper and rapid data‐processing is essential therefore.

Theinterventionsmay lose part of their effect through over‐determinancy or dynamically unfavourable (sluggish) responses. In either case statistical calculations disclose the average control errors that are liable to be made, and also the way in which these can be minimized.

Thesituationmay be unclear, i.e. the static and dynamic process characteristics are insufficiently known. In such cases regression and correlation techniques may aid in finding a solution.

Following a general review, we shall discuss in more detail those aspects that are bound up with the dynamics of the phenomena. Arguments from information theory reveal that the dynamic efficiency of control actions depends on correlation functions of time series (disturbances) and response curves of the systems (processes). The effects of disturbance correlation time, disturbance variance, sampling time, sample treatment, measuring errors, measuring time, rapidity of the intervention, etc., on the efficiency are elucidated by means of some formulae, graphs and examples.
Een toepassing van “importance sampling”
Authors: KLEIJNEN J. P. C.
Published: April 2008

Summary  This paper describes an experiment with “importance sampling”, to show how much reduction of the computation time and sample size can be achieved in comparison with the usual Monte Carlo method. A comparison is made between each of the three methods of “importance sampling” and the usual Monte Carlo method by the determination of the expression

Of the three methods A, B and C the first one uses the shifted exponential distribution, the second one uses the gamma distribution, and the third one uses the exponential distribution with modified parameter. These three methods have all smaller variances, ranges and sample sizes than the usual Monte Carlo method. Their order of preference is A, B, C. With respect to computing time only the method A is significantly better. So only the method A is an improvement in respect of both the sample size and the computing time.
Afschatting van verdelingen van kwadratische vormen met toepassingen op aanpassingstoetsen voor normaliteit en exponentialiteit
Authors: VAN SOEST J.
Published: April 2008

Summary  In this paper a simple approximation is given for the distribution of the quadratic form

being a weighted sum of squares of independent, identically distributed standardized normal variates. Using the formulae, the Monte Carlo results concerning some goodness of fit tests for normality and exponentiality are verified and extended.
Enige statistische aspecten van simulatie
Authors: LOMBAERS H. J. M.
Published: April 2008

Summary  When using simulation, the results of the computation should be analised to determine confidence limits and sensitivity. These can be improved by longer runs or by more sophisticated programming, both leading to increased cost. Some aspects of how to optimize simulation experiments are treated and of a simple queuing problem the influence of length of run, antithetic random numbers and control variables is compared with the analytical answers.
Forecasting the Past
Authors: HEESTERMAN A. R. G.
Published: April 2008

Samenvatting

Bezien wij het probleem van economische voorspelling. Wij nemen aan dat dit met een model gebeurt. Over dit model wordt de volgende veronderstelling gemaakt: Het model is een lineair stelsel van stochastische differentie‐vergelijkingen. Om een voorspelling te kunnen doen met behulp van het model, hebben wij cijfers nodig omtrent de uitgangstoestand. Deze uitgangstoestand behoort tot het recente verleden, waaromtrent de statistische informatie nog on‐volledig is. Dit doet het volgende probleem rijzen: Kan men het model ook gebruiken om de uitgangstoestand te “voorspellen”? Dit probleem verschilt van dat van het voorspellen van de toekomst, doordat we een additionele eis moeten stellen. De “voorspelde” vector van uitgangswaarden moet in overeenstemming zijn met de beperkte statistische informatie die wèl beschikbaar is. De auteur pakt dit probleem aan, door het minimaliseren van een gewogen som van de storingstermen in de afzonder‐lijke relaties van het model. Het algoritme, waartoe dit aanleiding geeft, wordt tamelijk gedetailleerd besproken.
Transforms for finding probabilities and variate values of a distribution function in tables of a related distribution function
Authors: Prins H. J.
Published: April 2008

Samenvatting

Het verband tussen enige bedkende verdelingen.

In dit artikel worden enkele schema's gegeven voor het verband tussen een aantal van de meest bekende verdelingen. Bovendien wordt een aantal andere relaties besproken. He doel van dit artikel is drieledig. Ten eerste kunnen statistische afdelingen, die in het bezit zijn van een uitgebreide tabellenverzamelign de gegeven transformaties gebruiken om bestaande tabellen uit andere tabellen te vervolledigen ten dienste van bepaalde praktische toepassingen. Ten tweede kunnen statistici, die niet in het bezit van volledige tabellenverzamelingen zijn, ontbreakende tabellen vervanden tussen deze verdelingen leiden tot meer inzicht in bepaalde toetsings‐methoden. Dit laatste punt wordt niet uitvoerig uitgewerkt.

Par. 1. geeft een inleiding en overzicht; par. 2 vermeldt de gebruikte symbolen en verwijst naar bekende tabellenverzamelingen; par. 3 en 4 geven schematisch de transformaties weer; par. 5 geeft een schematisch overzicht van de relaties; par. 6 geeft een aantal numerieke voorbeelden; in de appendix worden de wiskundige formules van de verdelingen vermeld.

Afleidingen worden niet gegeven.
Tabellen en nomogrammen voor het onderscheidingsver‐mogen van de 5% en 10%‐F‐toets voor het gebruik bij de gewarde blokkenproef
Authors: Keuls M.
Published: April 2008

Tables and graphs of the power of 5% and 10%‐F‐tests for use in randomized block experiments.

As randomized block experiments occur so often in agricultural and other research, it was thought worth while to adapt existing tables of the power of 5% F‐tests for this special case: The author hopes that in this way the design of experiments in terms of power will be facilitated. Moreover new tables were computed for the power of 10%‐F‐tests.

The tables have been summarized in graphs that greatly facilitate their use. Illustrations are given in practical problems.
Orde en wanorde*
Authors: van Soest J. L.
Published: April 2008

Order and disorder

The degree of order and of disorder are defined such that they are complementary and, each, vary between 0 and 1. Examples are given in problems of human life, of his community (with anarchistic and totalitarian extremes); also in thermodynamics (entropy) and information theory. In the latter problems the statistical quantity appears; it has quite the same meaning in both cases: the quantity of statistically weighted alternatives. The relation to entropy and to quantity of selective information is discussed. The degree of order 1 (degree of disorder 0) appears if this statistical quantity is 0, one of the p(i) being equal to 1 („frozen” or „pure” state). The degree of order 0 (degree of disorder 1) appears if this quantity is log n, all p(i) being equal to 1/n. The degree of disorder is equal to In information theory the degree of order is identical i=1 with redundancy. Order/disorder problems in patterns are related to Mark off chains of higher order and are not discussed here.
Het aselect kiezen van knopen in een knoopsel*
Authors: Bloemena A. R.
Published: April 2008

Random associations of points on a graph

Let be given a graph consisting of n points, numbered from 1, …, n, and mijjoins between points i and j. From this graph r points are chosen at random. This paper deals with the properties of a statisticx, being the number of joins between chosen points. Applications are considered to a test for randomness, and to the order‐disorder problem.

Analogous results for other statistics and also for the case in which the points are sampled independently of each other, are announced. These results are described in Bloemena, (1960).
De strijd tussen orde en wanorde, een optimumprobleem*
Authors: Harteveld R. B.
Published: April 2008

Order against disorder, an optimum problem

The whole of the production systems, presenting the social production apparatus, is not a chaotic, undifferentiated conglomerate, but shows a well‐defined structure. Internally, too, production systems display the most varied forms of differentiation.

This organization presents many advantages, but at the same time involves the need for coordination, i.e. the framing of equilibrated plans, in which the aims of the different sections are coordinated with the total purpose and in which the limitations of the available means are taken into account. Operational Research has arisen from the need for coordination, specially in those cases where phenomena are complex.

The function and the place of an operational research department in a concern can be learned about from Henry Fayol's study on the management of a concern.

The operational research department has a general staff function, directly subordinate to the supreme management, without any power to make decisions.

The use of mathematical techniques will never result automatically in the right decisions.

The quality of a model is determined by efficiency considerations. In each case the additional accuracy has to be weighed against the additional advantages. On economic considerations some measure of „disorder” has to be accepted.

The determination of the optimum quality of an O.R. model forms a problem which in practice can only be solved by the intuition of the O.R. specialist.
Aanvoer en opslag van dunne melk in een melkproduktenfabriek
Authors: van Kreveld A.
Published: April 2008

Summary

In a dairy products plant the problem arose that the milk‐carrying tankcars had considerable waiting times at the receiving platform. This was supposedly caused by too small a capacity of the raw milk storage room.

In order to study this problem the stream of milk through the storage room was followed for three weeks continuously. The storage room proved to operate mainly as a daily buffer. This function could be expressed in a linear equation. Its discussion led to some simple measures resulting in a considerable increase in efficiency of the storage room.

The study further proved that the waiting times of the tankcars were caused to only a small extent by the storage room capacity and that this effect could be eliminated by the above mentioned measures. It was concluded, therefore, that the storage room need not be enlarged.

The principal cause of the waiting times proved to be the limited unloading capacity of the receiving platform. And this in its turn was due to a strong periodicity in arrival frequencies of the cars. So, the solution of the problem had to be found in better car schedules, capable of breaking the periodicity.

Apart from this periodicity the capacity of the existing receiving platform was ample, as was shown by means of queuing theory.

Further, a special application of queuing theory was used to calculate the optimal design of a receiving platform. It was shown that few high capacity receiving installations are preferable to a larger number of smaller installations. The practical optimum is a platform of three installations.
Toegepaste statistiek*
Authors: Hamaker H. C.
Published: April 2008

Inaugural Lecture on applied statistics by Professor Hamaker at the Technical University of Eindhoven. A sketch about the role of applied statistics in the development of experimental science.

Mijne Heren Curatoren,

Mijne Heren Hoogleraren en Adviseurs,

Dames en Heren leden van de wetenschappelijke, de technische en de administratieve staven van deze Hogeschool,

Dames en Heren Studenten, en voorts Gij alien, die door Uw aanwezigheid van Uw belangstelling in deze plechtigheid blijk geeft,
The best quadratic estimator of the residual variance in regression analysis
Authors: Theil H. , Schweitzer A.
Published: April 2008

Samenvatting

De beste kwadratische schattingsfunctie van de storingsvariantie in regressie‐analyse.

Dit artikel handelt over de schatting van de variantie σ2 van de storingen in de regressieanalyse onder klassieke veronderstellingen: niet‐stochastische waarden aangenomen door de verklarende variabelen en normaliteit, onafhankelijkheid en homoskedasticiteit van de storingen. Bekend is dat de schatting volgens maximale aannemelijkheid neerkomt op net bepalen van de kwadratensom van de volgens kleinste‐kwadraten geschatte storingen en deling door T (het aantal waarne‐mingen); voorts, dat de schatting die minimale variantie heeft binnen de klasse van schattingsfuncties die zuiver zijn en kwadratisch in de afhankelijke variabele (de beste zuivere kwadratische schattingsfunctie) gevonden wordt door genoemde kwadratensom te delen door T–A, waarbij λ het aantal te schatten coëfficiënten is [d.w.z. het aantal verklarende variabelen (+ 1 indien een constante term aanwezig is)]. Hier wordt aangetoond, dat de schattingsfunctie van σ2 die een minimaal tweede moment heeft binnen de klasse van schattingsfuncties die kwadratisch zijn in de afhankelijke variabele (de beste kwadratische schattingsfunctie) gevonden wordt door de kwadratensom van de volgens kleinste kwadraten geschatte storingen te delen door T–Λ+ 2.
Een ontwikkelingsmodel voor India*
Authors: Sandee J.
Published: April 2008

A development model for India

A model for the economic development of India in the 1960—1970 period is described from the statistical point of view. The model contains 13 sectors, each with their specific products for which balance‐equations are set up. Input‐output and capital‐output relations connect the sectors. Agricultural output is linked to the use of fertilizer, irrigation and advice. Consumption in 1970 is maximized within 35 constraints. The paper winds up with a discussion of the effects of statistical uncertainties, and of possible improvements of the model.
Een wachtprobleem voorkomende bij drempelwaardemetingen aan het oog*
Authors: van Elteren Ph. , Gerrits H. J. M.
Published: April 2008

A queuing problem in connection with measurements of the threshold value of the human eye.

In the theory concerning the sensitivity of the eye the probability of perception W of a flash of light is considered as a function of:

the energy of the flash N̄

the duration of the flash t

the number of quanta k which must be effectively absorbed by the visual purple within a time τ and an area ω in order to perceive light.

If the area A of the spot of light on the retina is smaller than ω and t is smaller than τ, this function is simply the cumulative distribution function of a Poisson variable. Here the case A < ω but t > τ is considered. Then the chance W is the solution of a certain queuing problem.

In this way formulae for W of van der Velden (cf[I]) and Bouman and van der Velden (cf [3]) for the case k=2 are derived and new results are obtained for the case k=3. A new close approximation method due to dr. Runnenburg of the University of Amsterdam is given for the case k=2.
Van geval tot getal*
Authors: Meerdink J.
Published: April 2008

Results of experience may be based to a great extent on regularity of the phenomena observed and this is the fundamental base of statistics.

When comparing social sciences with technical or physical sciences, it must be emphasized that in the latter one single case may already be a subject of study, whereas in the social sciences observation relates generally to a multitude of facts. So the bearth of one of the oldest social sciences–economics–is the same as that of statistics. Other social sciences are still somewhat shy to use statistical methods.

A special feature is the need for economy when collecting figures, which has lead to an amazing development of sampling techniques. Moreover the use of mathematics in analysing statistical problems is mentioned.
Hoe groot is de steekproef?*
Authors: Vos J. W. E.
Published: April 2008

The effective size of stratified samples.

In this paper, the notion of effective size of a stratified sample is introduced, being defined as the total size of a stratified sample with optimum allocation over the strata that yields an estimate with the same sampling error as the sample concerned. The efficiency is defined as the ratio between the effective sample size and the actual size of the sample. This efficiency is rather low if allocation deviates considerably from the optimum.

Furthermore we define the marginal rate of return by the increase in effective sample size divided by the increase in sample size in one or some of the strata in an optimally allocated stratified sample. Finally the substitution rate of return indicates by how many elements the sample size in the remaining strata can be reduced if the effective sample size is to remain unchanged. A practical example is afforded in which the variances in the strata are assumed equal.
Over prijsraming en prijsvorming op de bouwmarkt
Authors: Bakker E.
Published: April 2008

The analysis deals with the ratio of actual to predicted prices of building projects for a big city in the Netherlands in the period 1946–1953. These forecasts had been made by the city's civil servants as a guide to building policy. It appears that the ratio of actual to predicted prices was of the order of 0.85 on the average, which implies a tendency to overestimate the actual prices to be paid. This ratio has an average which is closer to 1 for large projects than for small ones, and the standard deviation around the mean is smaller for large projects. Further more it appears that this standard deviation decreased systematically in the course of time.
Stochastische ∞‐staps beslissingsproblemen*)
Authors: de Leve G.
Published: April 2008

In this paper a survey of known methods for solving stochastic ∞‐stage decision problems is given. In addition a generalization for solving problems in which the state of the system is changing continuously in the course of time is discussed.
The estimation of the two‐dimensional distribution of a statistical set, based on the marginal distributions of its strata
Authors: Ivanovic B.
Published: April 2008

Samenvatting.

In dit artikel wordt een methode ontwikkeld, met behulp waarvan men de simul‐tane verdelingsfunctie F(x,y) van twee stochastische variabelen x en y kan aan‐passen, voor het geval dat de steekproeven van x en y onafhankelijk van elkaar ge‐nomen zijn.

De methode is gebaseerd op de veronderstelling dat de gehelepopulatie, waarop x en y betrekking hebben, bestaat uit een groot aantal subpopulaties; voor deze subpopulaties moet gelden dat de stochastische variabelen x en y dezelfde voor‐waardelijke verdelingsdichtheid f(x/y) hebben, terwijl alle voorwaardelijke ver‐delingsdichtheden f(y/x) verschillend moeten zijn. Daarnaast wordt aangegeven hoe men uit dezelfde gegevens de correlatiecoëfficient van x en y kan schatten. Als analogon van deze “enkelvoudige” correlatiecoefficient wordt de z.g. collec‐tieve correlatiecoëfficient van twee stochastische vectoren gedefinieerd, terwijl tenslotte wordt gedemonstreerd hoe het een en ander kan worden toegepast bij de voorspelling van het toekomstige verloop van tijdreeksen.
Vergelijking van een tweetal toetsen tegen verloop voor een aantal kansen
Authors: van der Gon J. J. Denier
Published: April 2008

Two test statistics t and b, testing equality of probabilities pi of success in k different series against the hypothesis of trend with given numbers gi (weights) of the series, are compared. The first teststatistic, due to C. van Ee den en J, Hemelrijk [1] is

with ni1 equal to the number of successes in ni trials and

Defining trend by

it appears that the teststatistic t gives rise to a test consistent for the complete set of alternatives τ≠ 0.

The other teststatistic is

b gives rise to a test which is not consistent for the general set of alternatives τ≠ 0 but for a rather important subset of these alternatives, i.e. those alternatives which show a lineair trend.

Neither of the tests in necessarily unbiased. The asymptotic relative efficiency of test t with respect to b is equal to or lower than unity. (Equal in case

n1= n2=…= nk with b = t;

in this case b is also consistent for the set of alternatives τ≠ 0). The variances of the teststatistics can be estimated with

Both tests are based on the approximately normal distribution of the teststatistics. To judge this approximation the 3rd and 4th cumulants of the distributions of the statistics are evaluated in terms of number of elements of a binomial distribution.

It is concluded that in case of possible non‐lineair relationships the teststatistic t is preferable as it gives rise to a consistent, designfree test. In case a lineair relationship has to be tested against the hypothesis of no trend the teststatistic b has to be prefierred, especially if the number of trials in the series are very different. An example is discussed.
An econometric analysis of factors determining contractors' interest in public tenders*
Authors: Bakker E.
Published: April 2008

Samenvatting

Het artikel behandelt de bepalendefactoren van de belangstelling van aannemers voor openbare aanbestedingen in Nederland in 1957. Defactoren, die in beschou‐wing zijn genomen zijn: de grootte van het werk ah kwantitatieve factor en de tijd van hetjaar, de aard van het werk en de opdrachtgever ah kwalitatieve factoren. Met kleinste kwadraten is het regressie‐verband bepaald van het aantal deelnemers aan een aanbesteding (belangstelling) en de logarithme van de inschrijfsom van de laagste inschrijver (grootte van het werk); ah de omvang van het werk het tien‐voudige is neemt het aantal deelnemers met gemiddeld 3 a 4 toe. De onverklaarde residuen zijn geanaliseerd naar de directe en interactie‐effecten van de kwalitatieve factoren. Met behulp van gewogen kleinste kwadraten is de kwantitatieve invloed van de voornaamste ejfecten geschat. De gegevens over de aanbestedingen zijn ontleend aan Cobouw en hebben betrekking op 1416 aanbestedingen in de sectoren grondwerk en wegenbouw.
, Algol 60“*
Authors: Dijkstra E. W.
Published: April 2008

The speaker illustrated the various features of the algorithmic language “ALGOL 60” by showing a simple but complete program written in this language. He stressed that these new means for expressing process descriptions are of great importance because they enlarge the group of potential computer users considerably.
Gissen en beslissen op statistische grondslag*
Authors: Goudriaan J.
Published: April 2008

Guessing and deciding on a statistical basis; a programm ‐ address to the general meeting of the Netherlands Statistical Society.

There is always a deep and dangerous gap between pure mathematics and any application of mathematics to some part of reality.

This danger is essential in the relatively new application of mathematical statistics to social sciences. ‘The observation of (nearly all) social phenomena is unique’1); they cannot be reproduced at will with sufficient accuracy; the recent and very valuable contributions to the theory of sampling are virtually useless in the social sciences. Therefore careful deductive analysis is a prerequisite for any successful statistical investigation in these fields.

Some examples are given of erroneous statistical interpretations in business economics, social economics and related subjects especially from recent american publications and suggestions are made for improvement.
On the predictive value of investment surveys1
Authors: Mouchart M. , Theil H. , Vorst J. I.
Published: April 2008

Samenvatting

Dit artikel handelt over de voorspellingskwaliteit van een tweetal investerings‐enquêtes, t.w. een voor de Duitse werktuigmachine‐industrie (uitgevoerd door het IFO‐Institut für Wirtschaftsforschung te München) en de C.B.S.‐enquête voor Nederland. Het Duitse materiaal betreft gegevens van individuele bedrijven, die perjaar de richting van de investeringen in het komendejaar voorspellen (stijging, geen verandering, doling) en daarnaast het investeringsbedrag (in D‐mark) over het afgelopen jaar opgeven. Het onderzoek laat zien, dat de bedrijven gemiddeld genomen te pessimistisch zijn in de zin dat de achteraf gemelde realisaties hoger liggen dan uit de tevoren gemaakte voorspellingen kan worden opgemaakt. Een dergelijke slagzij valt ook te constateren bij de C.B.S.‐enquête, die hier onderzocht is voor bedrijfstakken (niet voor afzonderlijke bedrijven). In tegenstelling tot de Duitse enquete is deze volledig numeriek: niet alleen de investeringsrealisaties, maar ook de voorspellingen zijn in guldens opgegeven. De neiging tot onderschatting van het investeringsniveau is sterk toegenomen toen het C.B.S. het oorspronkelijke criterium van het tijdstip van ingebruikneming van de investeringsgoederen verving door dat van het tijdstip van bestelling. Overigens vertonen de verschillende bedrijfstakken nogal wat variatie t.a.v. de onderschatting.
Het quotiënt van Von Neumann bij regressie‐analyse
Authors: Vermetten J. B. , Lisman J. H. C.
Published: April 2008

Some remarks are made concerning the application of the VON NEUMANN ratio in testing the residuals of a regression against serial correlation.

Special attention is paid to the fact that in general the VON NEUMANN ratio increases when first differences of the original variables are used.
Industriële Statistiek en Kwaliteitsbeleid in de toekomst*
Authors: Sieben J. W.
Published: April 2008

The use of statistical methods in quality control is discussed. In particular it is emphasized that the statistical techniques of experimental design should be used more generally and that consideration of the existing statistical methods from the point of view of control system theory will be necessary to obtain more efficient methods of quality control.