De plaats van de statisticus in het bedrijf

Summary  (The position of the statistician with regard to general management).
Analysis of the statistical work to be done in a great concern leads to a determination of the position of the statistician in the usual organisation scheme.     

De bewerking van veldproeven volgens de methode van Knut Vik

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.     

Toespraak door de directeur van de Stichting "Kwaliteitsdienst voor de Industrie"

Adress of the Director of the Foundation Industrial Quality Service.
The increasing of productivity also has an important qualitative aspect, To promote the qualitative increase of productivity the "Kwaliteitsdienst voor de Industrie" (Industrial Quality Service) wants to organize courses through which the statistical quality control methods can for each separate branch of industry be made available to those who are able to apply these methods, but who cannot spare the time and the energy required to take fully note of the mathematical and statistical backgrounds.     

Enkele opmerkingesn over de mogelijkheid van toepassing van mathematisch-statistische methoden bij tijdstudieproblemen en in het bijzonder bij het Bedaux-systeem

Summary  (Some remarks on the possibility of applying mathematical-statistical methods to time-study problems and in particular to the Bedaux system.)
Time and motion study are based on observations of the workman's movements and an estimation of his efficiency.
The time spent on a certain action in mass-production is not constant but shows a considerable variation, due to various causes. The time-study-man who investigates this action and expresses it in a rate, causes still more variations by certain inaccuracies in using the stopwatch and calculating the rate itself. Considered from a statistical point of view, these cumulating variations result in a standard-error in the calculated rate; this gives rise to some interesting phenomena.
A more statistical approach tot the whole problem is shown in this article to be possible.
In the discussion, the application of the Beaux-system is assumed, but the conclusions hold good for all time study systems.     

De bewerking van de resultaten van veldproeven door herleiding van de opbrengstcijfers in beide richtingen van het proefveld

Summary  (The treatment of the results of field experiments by reducing the yields in two directions)
Ir J. J. Dijkveld Stol has shown that good results have been obtained by reducing the yields of field experiments both in columns and in rows.
The mathematical foundation of this method is discussed in the preceding article and it is shown, that the method gives good results if the same supposition may be made as necessary for the application of the methods of Fisher, Knut Vik and the method of the differences.
The variance of Dijkveld Stol's method is identical with Fisher's error variance.     

Inleiding over de verdeling van extremen

Summary This paper is an introduction to the exact and asymptotic distribution of univariate statistical extremes and gives the methods of estimation of the parameters of the double exponential distribution.     

Statistische analyse van muziek

This paper presents an application of statistical methods in analysing music. By counting the notes in pieces of music, frequency distributions are obtained and analysed.
Particularly Bach's compositions are considered, which appear to be rather disciplined as to the use of the 12 notes in dependence of the key. Perhaps it would be possible to characterize different composers by means of these frequency distributions.
Also a specimen of modern music without any key is discussed.     

Environmental Statistics: Current and Future

Since 1900, statistics has prospered and established for itself a central place in science and technology, as can be seen from the wide application of its methods to almost all facets of life. The primary concern of statistics is to develop a logical and efficient system for information acquisition and analysis that is geared towards broad applications. Such a system has its roots and extensions in case studies from many scientific disciplines and in the collaboration between statisticians and other scientists. During the past three decades statisticians have become actively involved in the development and use of quantitative methods to understand and solve environmental problems. These activities are commonly called Environmetrics. In this paper we review the main features of current Environmetrics research and outreach activities. The paper is structured around typical examples drawn mainly from water quality and climate change to illustrate the type of problems involved, the statistical approaches used to address them, and the new statistical methods required for their solution. In addition we shall also briefly describe efforts made at the international level to link the statisticians working in the field together and with environmental scientists.     

Aantekeningen bij de herziening van de methodiek der prijsindexcijfers van het levensonderhoud

Momentarily (fall 196o) the Netherlands Central Bureau of Statistics is revising its price indexnumbers of family living. Some features of this revision are summarized below.
The old series is based on an expenditure pattern of 1951, whereas the new series will be calculated according to an expenditure pattern of 1959/'60. The latter data will be derived from a budget survey held among 250 households of manual and clerical workers consisting of 4 persons and grossing between four and eight thousand guilders a year (para. 6). The period covered was April 1959 till April i960.
The author indicates the way in which the varieties of the budget items to be covered by the monthly price surveys are chosen (para. 7). He discusses the principles and results of determining the number of price quotations (para. 8).
The choice of the municipalities in which price data will be collected is explained. An outline is given of the organisation of the new surveys apparatus (para. 14).     

Naar aseptische en realistische methoden in de toegepaste statistiek

Summary
Applied statistics is not pure mathematics but the application of suitable methods of mathematical statistics to practical problems.
In choosing the method one should be extremely suspicious in regard to septic methods and give strong preference to realistic methods.
Septic methods are those which by their very nature introduce properties alien to the magnitudes concerned e.g. addition of non-additive variables, differentiation of stochastic variables, stochastic treatment of indeterminate variables, etc. Realistic methods are those based on a preliminary analysis of the practical problem which should bring to light the essential mutually independent variables controlling the outcome of the problem. Undue simplification at the cost of the accuracy required in actual practice should be avoided; especially weak correlations between variables shown by the deductive analysis as being essentially mutually independent should be discarded.
On the other hand the mathematical treatment should be as simple and direct as possible.
The professional mathematician can become a real danger if he wants to guide the application of mathematical statistics to certain fields of applied science in which he is not sufficiently specialised and experienced. Contrariwise, if he acquires this knowledge in business, the highest positions are open to him.     

De statistiek van de Militair Geneeskundige Dienst

The author gives a review of the origin and use of the statistical material used in the medical corps of the Dutch army. He points out the value of employing the data in a statistical manner for planning the medical care of the troops.     

Drie soorten statistiek in de natuurkunde?

Summary  (Three kinds of statistics in physics).
A simplified derivation is given of the energy-distribution of Maxwell-Boltzmann, Bose-Einstein and Fermi-Dirac. The importance and the application of these laws are considered, and the fundamental hypotheses, on which they are based are mentioned.
It is shown that only one sort of statistics is used, but that the statistical method is adapted in each case to the special physical properties of the particles, to which this method is applied.     

De statistische basis van de planning in een machinefabriek

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.     

Een noodzakelijke correctie van de overschrijdingsgrenzen voor steekproefgemiddelden bij toepassing van stratified sampling

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.     

Eenvoudige mathode voor het interpreteeren van statistisch contröle-materiaal

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.     

Een steekproef ter vaststelling van de verdeling van de hoenderstapel

A sample estimate of the poultry distribution
In 1954 a sample survey was carried out of the returns of the agricultural census, May 1954, in order to establish the distribution of the number of holdings and the number of poultry, by size-group of arable land and by size-group of number of poultry. A simple 10 per cent, sample was planned and the expected variances of the numbers of poultry in each size-group were estimated beforehand. The method of estimation is indicated in this paper. This resulted in comparatively high relative errors in the size-groups above 500 hens and also in the size-groups of arable land. Therefore holdings with 500 hens and over were enumerated completely. Some tests were performed with the sample results and finally the efficiency of the stratification is discussed.     

Het voorspellen van levertijden uit gegevens over de voort-gang van een project

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.     

Mogelijkheden en moeilijkheden bij het toepassen van de sequentietest

Summary  (Possibilities and Difficulties in Applying Sequential Sampling)
The application of sequential sampling schemes may be much simplified by chasing H and b ( in Barnard's notation ) in such a way that H/(b+ 1) = integer and (b + 1) = integer. A decision to accept can now be taken only after each (b + 1) items and samples of (b + 1) items may therefore be chosen from the batch.
A handicap of H/(b + 1) points is now allowed to the batch. One point is added to the score whenever no defectives are found in the sample; 0, 1, 2, points are subtracted whenever respectively 1, 2, 3. … defectives are found in a sample. The acceptance boundary is 2H/(b + 1) points; the rejection boundary is 0 points.
For given 1 in 20 producer's and consumer's risk points ( p ₁% and p ₂%), values of H and b are given in table 1 and fig. 3.     

具有结构突变的CAPM的阶段异方差和自相关性的调整LM检验

由于金融市场是动荡不定的,资产定价模型CAPM往往会出现结构突变,异方差,序列相关,因此需要对CAPM的随机误差进行齐性检验。对于具有单个结构突变点的CAPM,本文得到了检验阶段异方差和自相关性的调整LM检验统计量。Monte Carlo模拟的结果显示,该调整LM检验统计量具有比普通LM检验统计量更好的检验功效。最后,我们用一个具体的实例论证了方法的有效性。