bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gesuperponeerde normale distributes en splitsing in elementaire curven
Authors: van Alphen G. W. H. M. 
Published: April 2008

SummaryThe splitting up of heterogeneous distributions into two normal componentsIt 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%.
De natuur als tegenspeler*
Authors: van Dantzig D. 
Published: April 2008

SummaryPlaying 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

SummaryTwo 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

SummarySome aspects of mathematical statisticsInaugural 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

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

SummaryThe 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

SummaryPrediction 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

SummaryPrediction 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

SummaryPrediction 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

SummaryRecapitulation.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

SummarySurvey of the development of the fisheries theoryA 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

SummaryTransformation of a frequency distributionA 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

SummaryOn 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

SummaryThis 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

SummaryThe 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

SummaryThe 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

SamenvattingDit 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 aan1/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

SummaryEstimation 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

SummaryStatistical aspects of musicWith 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

SummaryThe 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

SummaryInaugural 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

SummaryThe 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

SummaryA 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

SummaryChoice 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

SummaryThe 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 x02. 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

SummaryMarket 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.