bluuebunny/crossref_metadata_2025 huggingface dataset:
Kwaliteitsbeleid en Industriele Organisatie “MORGEN”
Authors: Willemze F. G.
Published: April 2008

Quality and Industrial Organisation: “To‐morrow”.

The influence of organised consumers, European integration and economic development on quality and organisation has been given.

A special way of organising from the bottom to the top has been explained. Emphasis has been placed on the necessity of and means of communication.
Another note on the delay problem in crossing a traffic stream.
Authors: Goudriaan J.
Published: April 2008

Samenvatting.

In dit artikel wordt hetzelfde vraagstuk behandeld als in dat van prof. dr. ir. J. W. COHEN in Statistica 17–1; het is gebaseerd op dezelfde algemene onder‐stellingen. Maar in plaats van uit te gaan van openingen (“gaps”) en verkeers‐stromen zonder onderbreking (“clusters”) richt het zich rechtstreeks op openingen van zodanige lengte dat dwarsverkeer mogelijk is (“Passes”) en ketens van één of meer voertuigen, eventueel gescheiden door kortere onderbrekingen, die geen dwarsverkeer toelaten (“Stops”). De tijd h in het artikel van COHEN is als een‐heid van tijd genomen.

Men komt dan gemakkelijk tot de algemeen geldende for mule voor de gemid‐delde wachttijd, een soortgelijke formule als gebruikelijk voor de gemiddelde wachttijd van een spoedorder in de fabrieksplanning wanneer geen onderbreking van onderhanden werk is toegelaten.

Deze formule geeft duidelijke aanwijzingen voor een organisatie van het verkeer, die de gemiddelde wachttijd tot een minimum maakt. Vervolgens wordt de samenhangonderzocht tussen de twee verschillende methoden van berekening en aan‐getoond, dat men de door COHEN gegeven resultaten in de voor de practijk belang‐rijke gevallen ook met een eenvoudiger en meer elementaire rekenwijze bereiken kan. Voor geval 1 en 3 van COHEN'S artikel is deze berekening nader uitgewerkt.
Generalization of Wilcoxon Statistic for the Case of k Samples.
Authors: Yen Elizabeth H.
Published: April 2008

Samenvatting

Doel van het volgende artikel is om aan te tonen, hoe verschillende bekende ranginvariante k‐steekproeven toetsen kunnen worden voortgebracht volgens één zelfdeprincipe. Dit principe is als volgt. Begin met de statistischegrootheden Uijen U0jvan WILCOXON te construeren (Uijuit de i‐de enj‐desteekproeven; U0juit de j‐de steekproefen alle andere tezamen; i, j = 1k). Laat vervolgens het symbool Tijde aanduiding zijn voor de genormaliseerde Uijen T0jvoor de genormali‐seerde U0j. Beschouw tenslotte de absolute waardeofhetkwadraatvaneenzodanige lineaire functie van de Tijof de T0j, dat deze absolute waarde ofditkwadraateen zo groot mogelijke waarde heeft (waarbij deze maximalisering plaats vindt over een geschikte verzameling van coëfficienten‐combinaties). Als resultaat verkrijgt men dan de toetsingsgrootheden van TERPSTRA, STEEL, KRUSKAL‐WALLIS, en een nieuwe toetsingsgrootheid.
Poisson‐proces met interrupties, een waarschijnlijkheids‐model voor het machinaal dunnen van bieten.
Authors: Zaat J. C. A.
Published: April 2008

Starting from the assumption that {even in case of dense precision sowing), the occurence of beet plants in a row can be taken as a realisation of a Poisson proces, the influence of mechanical thinning is studied.

The distribution of the distance between two plants, originally exponential, is changed by mechanical thinning in a way, dependent on the lengths of the intervals a (the potential survivor‐zone) and b (the length of the thinningblade).

The distribution of the distance between plants after mechanical thinning, is examined, and the “best” way of thinning, leading to the distribution of the distance between plants with the smallest variance, is derived.
Kwantificering in de sociologie
Authors: van der Voort E. M. Blok
Published: April 2008

Ensuing the recognition of indirect measurement of so‐called non‐measurable data in sociological research, many kinds of indices and scales have been constructed in order to grasp the essence of complex reality. Especially in the realm of attitude research the use of e.g. the GUTTMAN scale has been fruitful. Notwithstanding many critical remarks, new developments in scaling theory and scaling techniques warrant an optimistic view of sociology as an exact empirical science. More than up to now statistical thinking and methods will have to play a part in this development.
Communicatie en Organisatie*
Authors: van der Burg A. R.
Published: April 2008

A problem of communication arises as soon as the structure of an organization becomes too large for immediate total supervision.

There are 5 main types of immaterial communication: directing, instructing, coordinating, controlling and informing communication. In practice there are many shortcomings of communication. The main cause is its self‐generation. Part of the communication generates by pressure on the side of the expedient, part of it generates by drawing on the side of the recipient. The consequence is too much and too little communication.

For a good system of communication it is necessary to organize it instead of leaving it to uncontrollable forces of self‐generation. Some measures are given.
Convex transformations: A new approach to slcewness and kurtosis*
Authors: van Zwet W. R.
Published: April 2008

Samenvatting

In dit artikel worden een tweetal orde‐relaties voor waarschijnlijkheidsverde‐lingen voorgesteld, die ‐ beter dan de klassieke maten gebaseerd op derde en vierde momenten ‐ aangeven wanneer een verdeling een grotere scheefheid of kurtosis bezit dan een andere verdeling. Voorts wordt een aantal karakterise‐ringen en toepassingen van deze orde‐relaties behandeld. Bewijzen worden in dit artikel niet gegeven; deze zijn te vinden in een meer uitgebreide, aan dit onder‐werp gewijde studie [5].
Some mathematical aspects of reliability problems*
Authors: de Boer J.
Published: April 2008

Samenvatting

De vraag naar het verband tussen de betrouwbaarheid van een systeem en die van zijn onderdeien leidt tot problemen waarvan enkele behandeld worden. Bij systemen met overtolligheid {die de betrouwbaarheid niet altijd verhoogt) wordt onderscheid gemaakt tussen warme en koude reserves.

Elk van deze gevallen heeft een analogie met een bepaald wachtprobleem. Een practisch voorbeeld met een koude reserve wordt uitgewerkt.
Wachten in het wegverkeer*
Authors: de Lange S. J.
Published: April 2008

First a brief survey of different waiting situations in road traffic is given, classified after the applicability ofqueueing theory. In section 3 and 4 is indicated to what extent queueing theory may be used to solve problems related to respectively, an intersection with fixed‐cycle traffic lights, and to the crossing of a highway.

The article concludes with some considerations about the interpretation of mean waiting time.
On a waiting time problem in physiology
Authors: ten Hoopen M. , Reuver H. A.
Published: April 2008

Samenvatting

Voor een wachttijdprobleem, dat ter sprake komt in de quantum theorie van de visuele waarneming en bij een onderwerp uit de theoretische neurofysiologie, wordt een benaderde oplossing gegeven.

Vergelijkingen worden gemaakt met de exacte oplossing en met uitkomsten van een Monte Carlo simulatie.
Interne leveringen in de inzet‐afzetanalyse
Authors: Neudecker H.
Published: April 2008

Summary

By applying this relation all results in the two definition systems can be translated into each other. In this note we will analyze some relationships between increments in gross and net production.

It turns out that in case the external delivery structure changes {the non‐diagonal coefficients of A), relative increments in gross and net production are identical.

A further result is that neither relative nor absolute increments in gross and net production are identical in case of changes in the internal delivery structure {the diagonal coefficients of A).

The third result is that relative increments in gross and net production are identical in case of a change in final demand.

Input‐output analysis can be set up in gross or net terms. In the first case the internal deliveries of a sector are included in the table, in the other case they are neglected. These two different approaches give rise to two different leontief matrices: A and D.

Stone determined a relation between the two matrix multipliers (I‐A)‐1 and (I‐D)‐1
Wiskunde en besliskunde
Authors: Kriens J. , Aandacht Ik dank U voor Uw
Published: April 2008

Mijne Heren Curatoren en Leden van de Raad van Toezicht, Mijne Heren Professoren, Lectoren en Docenten, Dames en Heren Leden van de Wetenschappelijke Staf, Dames en Heren Studenten en voorts Gij alien, die door Uw aanwezigheid blijk geeft van Uw belangstelling,
Automatic processing of quality data of rayon tire yarns and cords*
Authors: Ottens F.
Published: April 2008

Samenvatting

Als voorbeeld voor automatische verwerking van kwaliteitsgegevens wordt een systeem beschreven voor het verwerken van een aantal garen‐ en koordeigen‐schappén van alle in de Nederlandse AKU‐bedrijven gesponnen rayon banden‐garens. Het routine‐onderzoek van de monsters wordt uitgevoerd op een Centraal Laboratorium, terwijl voor de bewerking van de waarnemingsuitkomsten gebruik wordt gemaakt van een tweetal computers (EL‐X1 en IBM 1401) van het AKU‐Rekencentrum.

Eerst wordt de gang van zaken op het laboratorium en op het Rekencentrum besproken, waarna de, in de computerprogramma's ingebouwde, rekenkundige en statistische procedures uitvoerig worden toegelicht. Besloten wordt met een opsomming van de voordelen, welke door de invoering van het systeem zijn verkregen.
Variantieanalyse met behulp van een computer*
Authors: Kuipers H. A.
Published: April 2008

Analysis of variance with the aid of a computer

The outlines are given of a multi‐purpose program for the analysis of a factorial design with at most four factors by means of an electronic computer. Special attention is paid to its possibilities and to the difficulties which can arise in designing such a program, that is to be used for more than one purpose, e.g. for a simple Student‐test as well as for fitting regression lines, testing their parallelism and determining their horizontal distances.
Enkele algemene beschouwingen in verband met de uit‐voering van het Deltaplan*
Authors: Dronkers Dr. J. J.
Published: April 2008

The object of this paper is to show some statistical investigations concerning the determination of the design of the dams of the Delta Plan in the Netherlands.

For the determination of the height of the dams, regarding overflow, statistical analysis must be applied on the actual observations of stormflood levels and wave heights. The extrapolation of the frequency curves of these data is one of the basic problems. The frequency curves of wave heights, periods etc. are determined by means of an electronic computer. An important object of study is the wave attack on the dam or dike. The damage due to wave attack will usually be determined by means of model wave tests in an Hydraulic Laboratory. The results determine the shape of the dike, especially the incline of the slopes and the materials of which the slope is constructed e.g. stone or asphalt.

The economic decision problem shows the background of the determination of the optimal dike construction, in connection with the amount of money to be invested in dikebuilding: after optimal dike construction the expected capitalized values of all future losses by damage and the costs to be invested must be minimal. It is clear that the determination of these expected losses also depends on statistical investigations.
Een studie omtrent de cirkulatie van materieel*
Authors: van Rees J.
Published: April 2008

The circulation of rolling‐stock‐units in a scheduled transportation system is formulated in terms of Flows In Networks.

This formulation enables us to develop a convenient method to find a circulation of rolling‐stock which is optimal with respect to the total cost.

Basic data are the time‐table and the capacity, needed in each scheduled train, tram, bus or flight. In addition also the case in which there are two different types of rolling‐stock‐units with respect to their capacity is considered. Especially the rate of using the two types is investigated against total cost.
Enige ervaringen bij de ontwikkeling van een standaard‐toetsingsprogramma*
Authors: Mokken R. J.
Published: April 2008

The continuous improvement in velocity and capacity in the construction of modern computers, the development of programming languages and the possibilities of exchange and wider application of programmes might easily lead the uninitiated to overoptimistic views and expectations considering the saving of time and even the elimination of programming effort.
Opmerkingen en berekeningen betreffende “Poisson‐proces met interrupties” van J. C. A. Zaat
Authors: Runnenburg J. Th. , Vervaat W.
Published: April 2008

Summary

In an earlier paper by J.C. A. ZAAT an interrupted Poisson process was studied. Here we clarify some of the results there obtained. The process is obtained from a stationary Poisson process on the real axis by covering the axis with a sequence of adjoining intervals which have alternatively length a and b, the first left‐hand endpoint of an a‐interval to the right of 0 being chosen in a stochastic point n̈ with n̈ <a + b, where y is independent of the Poisson process, and omitting the points indicated by the Poisson process in the intervals with length b. It is here shown, that the distribution of the length of an interval between two successive points in the interrupted Poisson process is the same for all intervals that do not contain 0 if and only if n̈ has a rectangular distribution over [b, a + b]. The interrupted process is periodic and non‐stationary. The common distribution function of the interval lengths in the interrupted process is denoted by G(y). Its Laplace‐Stieltjes transform is obtained.

Ifn̈ has a rectangular distribution on [0, a + b] the interrupted Poisson process is stationary, but the distribution of the length of an interval between two successive points in the interrupted process is now different for different intervals. For each distribution ofy over [0, a + b] the distribution of the length of the interval between the nth and the (n + I)st point to the right ofO in the interrupted Poisson process tends to the distribution function G(y) as n tends to infinity. Somehow ZAAT based his calculations exclusively on this stationary distribution.
Een prijsindex van nieuwe personenauto's, 1950–1965*
Authors: Cramer J. S.
Published: April 2008

Summary

In constructing a price index of new motorcars the main problem is how to deal with the introduction of new models and with quality variation generally. The first difficulty is turned by compiling year‐to‐year indices based on models that each account for 2 per cent or more of total sales in either year. The shifting basis of these indices comprises from 7 to 15 models which together account for 45 to 70 per cent of total registrations. All models are subject to minor improvements; this quality variation is taken into account by representing increases in horse power and overall length by equivalent price reductions. The elasticity coefficients involved in this translation are derived from a cross section analysis of prices and technical characteristics of some fifty widely ranging models in 1964.

A price index for the period from 1950 to 1965 is then obtained by linking successive year‐to‐year indices. Over the whole period list prices have risen by a third, to a large extent as the result of changes in purchase tax; this price rise is just about offset by imporvements in quality of some 2 per cent per annum.
De fout bij het gebruik van een tweetal benaderingsformules
Authors: van Noerssen R. F.
Published: April 2008

Summary

For the sake of efficiency, the use of simplified formulae in item analysis is recommended. For adequate use of such formulae the systematic error must be known. For two important formulae this error is estimated: the KUDER‐RICHARD‐SON‐21 (instead of 20) and a formula for the correction of the spurious part‐whole correlation.

As for the KR, if itemscores are 1 andO, the KR20 is given in (I) and the KR21 in (2). The difference dr between them, given in (5), is directly proportional to the variance of the itemdifficulties. This variance turns out to be rarely greater than 0,05. If the distribution of itemdifficulties is unimodal, a value greater than 0,05 is indeed improbable in four‐choice tests. The KR21, which does not need an item analysis, can be used as a substitute of the KR20. The KR21 coefficient itself is an lower limit, the KR21 plus dr ‐ estimated by (6) ‐ a probable upper limit of the KR20 coefficient.

The part‐whole correlation of tests is spurious. If one wants to correct for this spuriousness it is theoretically preferable to estimate the part‐parallel test correlation instead ofthe part rest correlation. This is done here with the assumptions of classical test theory. The part‐parallel test correlation is given in (12), the easily computed first approximation, called A, in (13) and the second approximation in (75), in which last formula the corrected correlation is expressed as a function of A, the standard deviations of part and whole, and the reliability of the test. One can compute with this formula a maximum A, below which the first approximation is sufficiently precise.
Sturen met statistiek*
Authors: Hogerzeil H. H. W.
Published: April 2008

Summary

Reliable information on a morbidity pattern of a population can give us comprehensive ideas how the medical care, and a medical research programme must be organized.

To get this reliable information operational methods have to be used. These methods are dealt with in this article.

Some suggestions and conclusions for a health care policy are given.
Tolerantiegebieden en toetsen voor Kwantielen*
Authors: Adriaanse R. P.
Published: April 2008

Summary

After some general remarks about tolerance regions two simple cases are considered: the distribution‐free tolerance region and a one‐sided tolerance region for a normal distribution. For a p‐content tolerance region at confidence level γ the equivalent hypothesis‐testing problem is considered which, as a special case, includes the one sided quantile‐tests.
Statistiek en planning in de sociale sector*
Authors: Verstegt J. Ch. W.
Published: April 2008

Summary

Statistics and planning do not function as yet in the social sector in the same way as they do in the economic sector, where national accounts and balances are used as frameworks for the integration of the various economic statistics.

On the one hand economic sector studies can be made for the social sector as well, giving a picture of the total costs and the financing of the various kinds of social care; on the other hand it is necessary that for each kind of social care (education, medical care, care for the maintainance of law, order and safety, religious care, care for labour and spending of leisure time, housing and social work) social input‐output tables be composed regarding the “cared‐for” as well as the “caretakers”, giving in the form of a matrix the flows of persons passing through each sector of care.

If projections are based on such matrices, planning becomes possible and in this way shortages and surpluses can be located in time and a long term policy can be pursued.

The various basic statistics will have to be brought into harmony with the requirements of the composition of such input‐output tables for each cohort. To reach this goal two ways are open: either by collecting information for each individual entering a care‐sector about one or more previous situations or by following the individuals through various situations of entering, passing through and leaving care‐sectors. This latter method, the method of the so‐called longitudinal statistics, provides greater possibilities because extrapolation is easier and one can link the different previous situations. The relevant factors can be quantified and the data for model building become available.

The development in registration and in automation makes the compilation of longitudinal statistics ‐far as necessary on a sample basis ‐ a practical possibility.
A Sequential distribution‐free two‐sample grouped test with three possible decisions*
Authors: van der Laan P.
Published: April 2008

Summary

A sequential two‐sample grouped rank test with two possible decisions (onesided testing) developed by WILCOXON, RHODES and BRADLEY (1963) is generalized to a sequential test with three possible decisions (two‐sided testing) using a method given by SOBEL and WALD (1949). An auxiliary table with some moments concerning LEHMANN'S alternatives for the normal distribution, is given in order to facilitate the choice of the alternative hypotheses.
Bias in estimation from type I censored samples
Authors: van Zwet W. R.
Published: April 2008

Summary

Let be a family of probability distributions on R1. This paper raises the question whether a parameter θ=θ (P), Pt, is estimable on the basis of a type I censored sample (i.e. censored on a fixed set C). Two theorems are given that state conditions on θ and C that ensure that θ is not estimable. The results are applied to estimation problems for the normal and POISSON distributions; it turns out that unbiased estimation is impossible in the majority of practical cases.
Steekproeven uit de halve cauchy verdeling
Authors: MIJNHEER J. L.
Published: April 2008

Summary  Let x1…, xn be a sample from a distribution with infinite expectation, then for n→∞ the sample average x̄n tends to +∞ with probability 1 (see [4]).

Sometimes x̄n contains high jumps due to large observations. In this paper we consider samples from the “absolute Cauchy” distribution. In practice, on may consider the logarithm of the observations as a sample from a normal distribution. So we found in our simulation. After rejecting the log‐normality assumption, one will be tempted to regard the extreme observations as outliers. It is shown that the discarding of the outlying observations gives an underestimation of the expectation, variance and 99 percentile of the actual distribution.
Een indelingsprobleem
Authors: ANTHONISSE JAC. M.
Published: April 2008

Summary  A branch and bound algorithm is given to solve the following problem: To each pair of elements (i,j) from a set X={l,…, n} a number rij with rij≥ 0, rij=rij and rij= 0 has been assigned. Find a prescribed number of disjoint subsets P1…,Pm from X, such that

Experiments indicate that an optimal solution is usually found in a small number of iterations, but the verification may be rather time consuming.

The algorithm may be used to find the minimum value of m for which a partitioning of X with z= 0 exists. The algorithm appears to be efficient for finding this ‘chromatic number of a graph’.
Autoverkopen en autopark in Nederland, 1950–1970
Authors: CRAMER J. S.
Published: April 2008

Summary  This is a study of the demand for the ownership of new or firsthand cars, i.e. the demand of ‘first owners’ who habitually buy new cars which are then traded in long before they are obsolescent. Upon combining the evidence of various surveys with time‐series for 1950‐64 it is found that this ownership has an income elasticity of 2 and a price elasticity of – 1.25 in respect of the constant‐quality index of new car prices earlier provided. On the average new cars are traded in after three years so that roughly one third of the existing stock is replaced every year. These values together determine an equation for purchases of new cars which accurately predicts new registrations in 1965 and 1966. Projections for the years 1967‐70 are provided.

In the model employed the total number of cars (including used cars) is determined by the active demand exerted by ‘first owners’ on one hand and by the hitherto fairly constant scrappage rates on the other. Projections of the overall ownership rate can therefore be derived from the forecasts of new registrations. The ownership rate will approach 80% around 1970, and it is likely that at that stage the current scrappage rates will cease to apply in view of the greater predilection for comparatively younger cars.
Het rekenkundig gemiddelde stijgingspercentage – een ondoelmatige groei‐indicator
Authors: TILANUS C. B.
Published: April 2008

Summary  In business practice it happens that annual growth is measured by the ordinary (arithmetic) average of yearly growth percentages. It is argued that there are better methods in any case. A method requiring relatively much time is least squares. Methods requiring very little time are a) determining growth graphically, using semi‐logarithmic graph paper b) computing the geometrical average, which is nothing else than the n‐th root (if there are n+l observations) of the ratio between the last and first observation.

In a table, a survey of bias and dispersion of three estimators is given for a few numerical cases.
Representation of ANOVA models with vectors and vector spaces
Authors: Verdooren L. R.
Published: April 2008

Summary The use of vectors and vector spaces for the representation of the fixed‐effects models for the analysis of variance (ANOVA) is well‐known. This representation gives a clear understanding of the estimation and hypothesis testing problems.

A similar representation can be used for the random‐effects models and some mixed models. As a result the distribution and the expectation of the mean squares in the ANOVA table can easily be derived.
Back to “Back to the Laplace definition”
Authors: Rootselaar B. van , Hemelrijk J.
Published: April 2008

Summary The purpose of this paper is to present some corrections and supplements to the second author's papers [2] and [3] in this journal. It is a result of a discussion of the first author's criticism, which was directed against two points, viz. first the presentation of the paradoxes of Zeno from Elea ([3], § 2) and second some technical aspects of the introduction of probability by means of the notion of randomizer ([3], § 5).
Rechtszekerheid bij onzekerheid
Authors: Sittig J.
Published: April 2008

Legal security under uncertainty

There are two sources of losses in decision making: collective judgment and uncertainty. The situation can be summarized as follows:

Minimization of losses can be achieved by using optimal decision rules. The effect of this method differs in the three cases treated. The analogies and differences of the three cases are discussed in this paper.

Lezing gehouden op de Statistische Dag 1969.
Some remarks concerning the quotient of sample median and sample range for a sample of size 2n+1 from a normal distribution
Authors: Haan L. de , Runnenburg J. Th.
Published: April 2008

Introduction and summary

Consider an ordered sample (1), (2),…, (2n+1) of size 2n+1 from the normal distribution with parameters μ and s̀. We then have with probability one

(1) < (2) < … < (2n+1).

The random variable

n
=(n+1)/(2n+1)‐(1)

that can be described as the quotient of the sample median and the sample range, provides us with an estimate for μ/s̀, that is easy to calculate. To calculate the distribution of hn is quite a different matter***. The distribution function of h1, and the density of h2 are given in section 1. Our results seem hardly promising for general hn. In section 2 it is shown that hn is asymptotically normal.

In the sequel we suppose μ= 0 and s̀= 1, i.e. we consider only the “central” distribution. Note that hn can be used as a test statistic replacing Student's t. In that case the central hn is all that is needed.
Suggestie betreffende het combineren van overschrijdingskansen
Authors: Kroon J. El. M. de
Published: April 2008

Summary In this paper a new method for combining P‐values is suggested. This method takes into account that the P‐values to be combined may be based upon different numbers of degrees of freedom.
Investeren en onzekerheid
Authors: Verheyen P. A.
Published: April 2008

Summary Investment and uncertainty

After a few introductory remarks about the necessity of uniform definitions about plan horizon, returns, expenses, interest factor ett. for all investment alternatives and the necessity of an also uniform way of prediction, several models on investment analysis which are known from literature are briefly discussed. For simplicity there is only one decision variable (i.e. capacity); the variables influencing it are called exogeneous variables. These exogeneous variables may be deterministic and then one has to maximize the sum of the discounted cash flows from each project where different levels of investment into a project are supposed to exclude each other. The maximization may be subject to restrictions or not. If the exogeneous variables are stochastic one has to maximize the expected utility, mostly defined by the expected value and the variance of the discounted cash flows. The way to carry this out is simulation. Also portfolio analysis may be used, but there are some objections against this method, which are discussed.
Short‐run auction price adjustments
Authors: Burley S. P.
Published: April 2008

Summary Daily prices at the Pijnacker agricultural auctions were analyzed by some new spectral techniques based on the fast Fourier transform. Within the context of linear theory, it was found that the short‐run variations in prices could be described by a random‐walk model. No significant correlation was observed between these price movements and the short‐run fluctuations in the amounts sold. Even the strong weekly cycle in supplies had no matching effect on prices.
On certain type of Queues in series
Authors: Maggu Parkash Lal
Published: April 2008

SummaryThis paper studies the steady‐state behaviour of a queueing system consisting of three servers S1,S2andS3. Two types of units each requiring two phases of service arrive and form two queuesQ1andQ2in‐front of the two serversS1and S2, respectively, which attend to their first phase of service in order of arrival. On completion of the first phase the units discharged from these servers from a single queueQ3in‐front of S3for the phase 2 service. The various stochastic processes namely, the interrarrival times and the service times, have been assumed to be distributed exponentially. We derive for this queueing process an expression for the mean queue length and some particular cases thereof.
On applied econometric research
Authors: Heesterman A. R. G.
Published: April 2008

Summary This paper discusses criteria by which one may investigate whether stochastic relations and models are correctly specified. In this connection, the concept of the systematic coincidence arises. A systematic coincidence is a specified relationship, which, on closer analysis, appears to be the result of simultaneous interdependence via the model as a whole, and not a valid relation in its own right at all. The problem is then surveyed from the point of view of the practical research worker, and the emphasis is on time‐series analysis.
Confidence intervals for batch properties based on both sampling and analytical variance
Authors: Kalmijn W. M.
Published: April 2008

Summary If different random samples are taken from a heterogeneous batch and each sample is analysed once or in replicate, the average result is a point estimation of the true but unknown mean of the batch property concerned. In this paper, formulae are given for the numbers of degrees of freedom, which are necessary for interval estimations based on both the sampling and the analytical variance. It is essential to distinguish between situations in which estimates of the variances are available and in which they are not.
Arm ‐ en ‐ rijk oftewel: leren ‐ de dommekracht onder de inkomenslift*
Authors: Somermeijer W. H.
Published: April 2008

Summary This address deals with factors contributing to the inequality of income, with particular reference to the Netherlands and to the U.S.A. Sections 2 and 3 survey the shape of the income distribution curve, and the (possible) impact of the length of the reference period and of capital income on income variance.

Section 4 shows the modest contribution of intergroup (compared with intra‐group) differences in (mean) income, after classification of income recipients by occupation, age and sex.

Special attention is paid to estimation of schooling and intelligence effects in multivariate analysis. All systematic factors taken together appear to account for less than 1/3 of the total income variance, so that a major part of it is still unexplained; mainly entrepreneurial income seems to be responsible for it.

Finally, possible changes in income distribution ‐ autonomous or resulting from policy measures ‐are discussed summarily.
Note on the generation of most probable frequency distributions
Authors: Lisman J. H. C. , Zuylen M. C. A. van
Published: April 2008

The most probable distribution of a stochastic variable is obtained by maximizing the entropy of its distribution under given constraints, by applying Lagrange's procedure.

The constraints then determine the type of frequency distribution. The above holds for continuous as well as for discrete distributions.

In this note we give a survey of various constraints and the corresponding frequency distributions.
Estimation in sampling on two successive occasions
Authors: Avadhani M. S. , Sukhatme B. V.
Published: April 2008

For estimating the mean of a finite population on the second of two successive occasions from a simple random sample, the authors [1] have proposedelsewhere an estimate which utilizes the data obtained from the sample on the first occasion as ancillary information. In this paper, it is shown that this estimate is more efficient than the one similar to that of Pathakand Rao[2] in all situations where the well known ratio estimate in simple random sampling is no less efficient than the usual regression estimate or the Rao‐Hartley‐Cochranestimate in sampling with varying probabilities and without replacement.
A method for taking road traffic censuses
Authors: Derksen J. B. D.
Published: April 2008

For some time the department of Statistical analysis of the Netherlands Central Bureau of Statistics has been engaged in developing sampling methods for taking road traffic censuses. This paper summarizes work that is being done on designing methods for traffic surveys on State and provincial roads.
Een lading van kraaltjes
Authors: Buhrman J. M.
Published: April 2008

Summary An urn containing 200 red beads and 1000 yellow ones is frequently used for demonstration of the hypergeometric or binomial distribution. Experiments show that the practical frequency distribution differs slightly but definitely from the theoretical one. This deviation turned out to be caused by electro‐static forces.
The distribution of lifetime earnings: a problem of intertemporal aggregation
Authors: Fase M. M. G.
Published: April 2008

Summary The main reason to study lifetime earnings as opposed to annual earnings is that the former are purged of life cycle influences. If annual earnings are described by a random variable, it logically follows that lifetime earnings are also random. This paper examines the implications of this statement, starting from the basic assumption that annual earnings of a new entrant to the labor force are a drawing from a two parameter lognormal distribution. It is found that the probability distribution function of lifetime earnings can be derived explicitly if one is willing to define lifetime earnings as a geometric mean.
Variables sampling plans for the Poisson and the binomial
Authors: Guenther William C.
Published: April 2008

Variables sampling plans based upon continuous distributions are well known. The usual assumption is that a measurable characteristic associated with a product has a normal distribution, a case which has been treated extensively in the literature. Other continuous distributions, particularly the exponential, have also been used as models. In this paper we discuss variables sampling plans for situations in which the measurable characteristic has either a Poisson or a binomial distribution.
Repeated testing for outliers
Authors: Hawkins Douglas M.
Published: April 2008

Summary The paper deals with the type I error probabilities when a single outlier test is applied repeatedly to a sample. In the case in which multiple outliers are present, expressions for the power loss due to masking are derived.
A priority queueing system with service interruptions
Authors: Madan K. C.
Published: April 2008

This paper studies a queueing system in which a mechanical service channel serves the units one by one on a priority basis and is subject to occasional breakdowns. During the period for which the mechanical service channel remains under repairs, the service is provided to only the units of priority class by a manually operated service channel. Laplacetransforms of the probability generating functions of the queue length have been obtained and the corresponding results for the steady state have been derived. Finally a particular case has been discussed.
Some ideas and models in reliability theory
Authors: Cohen J. W.
Published: April 2008

SummarySome questions about the meaning of reliability for the design of complex systems are discussed. Should the ideas of reliability be put in a broader framework, becoming applicable also to nontechnical systems, like a government organisation? In the mnd chapter some rather new failure models are reviewed and an interesting derivation of the Weibull distribution is discussed.
Practical recipes to solve the Behrens‐Fisher problem
Authors: Thomasse A. H.
Published: April 2008

Abstract  The comparison of the unknown means of two populations with unknown variances is called the Behrens‐Fisher problem, if the populations are assumed to be normal and the ratio of the variances is not known. In this paper a summary of recipes is given to solve this problem in practice, as published in the past 35 years by Banerjee, Fisher and Behrens, Pagurova, Wald and Hajek, Welch, Welch and Aspin, together with two large sample solutions and one solution often used as an approximate one without justification.

The solutions are presented mainly in terms of confidence intervals for the difference of the population means. Some remarks are made concerning the lengths of these intervals and the power of the corresponding tests. The solutions in this paper are dependent on the means and the variances of samples drawn from the two populations only. All solutions discussed, except the disqualified approximate one, are robust against violations of the normality assumptions with respect to the populations and they provide, at least asymptotically, good measures for the difference of the population means if the samples are drawn from populations whatsoever with finite second moment.
An empirical Bayes rule for testing simple hypothesis against simple alternative
Authors: van Houwelingen J. C.
Published: April 2008

This paper gives a short introduction into the empirical Bayes approach. To illustrate this approach the classical problem of testing a simple hypothesis against a simple alternative is discussed. Some explicit results are given for testing Ho: N(‐1, 1) against H,: N(1, 1). This paper is a further elaboration of section 3.1 of the author's dissertation Wan Houwelingen (1973)).
Optimale rantsoenering van aardolie en aardolieprodukten in Nederland; een toepassing van input‐outputanalyse en lineaire programmering
Authors: Kreijger R. G. , Rouwens T.
Published: April 2008

Samenvatting Bij een invoerrestrictie van ruwe olie ontstaat het probleem van de optimale verdeling van de olie over de verschillende bedrijfstakken. Met behulp van input‐outputanalyse kan dit probleem worden getransformeerd in een lineair‐prograrnmeringsvraagstuk. In het navolgende artikel worden een aantal oplossingen gepresenteerd die men verkrijgt bij verschillende veronderstellingen omtrent bezuinigingsmogelijkheden, verbruiksminima enz.
Enige ervaringen met kursussen in de OR met behulp van management games
Authors: Droppert A. J.
Published: April 2008

Samenvatting Binnen Akzo is veel ervaring opgedaan met speciaal voor dit doel ontwikkelde managementgames in OR‐cursussen. Het blijkt dat deze van grote waarde zijn zowel om de motivatie te verhogen als om het inzicht te verdiepen in de toepassingsmogelijkheden van OR in de praktijk.

In dit artikel worden een tweetal cursussen beschreven en de plaats hierin van de games. Een aantal praktische ervaringen worden genoemd.

De cursussen die hier beschreven zijn bereiken door de grote motivatie van de cursisten en de vrijere wijze van doceren veel beter hun doel dan meer technische cursussen. Het instrument van het management game draagt hier zeer wezenlijk toe bij.
Optimal designs for linear mixture models
Authors: Mendieta E. J. , Linssen H. N. , Doornbos R.
Published: April 2008

Summary In a recent paper Snee and Marquardt [8] considered designs for linear mixture models, where the components are subject to individual lower and/or upper bounds. When the number of components is large their algorithm XVERT yields designs far too extensive for practical purposes.

The purpose of this paper is to describe a numerical procedure resulting in a design of fixed size N, which is approximately D‐optimal, and where the components may be subject to linear constraints (f.e. upper or lower bounds). The proposed method is more generally applicable for models linear in the independent variables and the parameters and the convex hull of the experimental region is a polyhedron whose vertices are known.
A property of Stein's estimator for the mean of a multivariate normal distribution
Authors: Susarla V.
Published: April 2008

A uniform bound on the risk (under squared error loss) of Stein's estimator Ψ1 for the mean of the multivariate normal distribution is given. Using the bound, the asymptotic behaviour of the risk of Ψ1 under a Bayesian assumption is obtained.
Minimizing maximum lateness on one machine: computational experience and some applications
Authors: Lageweg B. J. , Lenstra J. K. , Kan A. H. G. Rinnooy
Published: April 2008

We consider the problem of scheduling jobs on a single machine subject to given release dates and precedence constraints, in order to minimize maximum lateness. The algorithms of Baker and Su (Naval Res. Logist. Quart. 21 (1974) 171–176) and of McMahon and Florian (Operations Res. 23 (1975) 475–482) for the problem without precedence constraints are extended to the general case. An extensive computational comparison establishes the superiority of the latter algorithm. We describe applications to the theory of job‐shop scheduling and to a practical scheduling situation.
Identification in statistical inference
Authors: VAN DER GENUGTEN B. B.
Published: April 2008

The paper deals with the concept of identification in inferential statistics. At first a general concept of identification is defined and developed. Thereafter, the general theory is applied to univariate linear regression and simultaneous equation systems. Finally, attention is paid to models with lagged variables and some new related problems are suggested.
Monotonizing empirical Bayes estimators for a class of of discrete distributions with monotone likelihood ratio
Authors: VAN HOUWELINGEN J. C.
Published: April 2008

A procedure is given for the construction of a monotone estimator that dominates a given estimator for a class of discrete distributions with monotone likelihood ratio. This procedure is applied to some empirical Bayes estimators. Monte Carlo results are given that demonstrate the usefulness of monotonizing.
A simultaneous econometric model for the Dutch economy
Authors: KETELLAPPER R. H. , BOS B. , KOOYMAN M. A. , VOORHOEVE W.
Published: April 2008

Abstract  This paper gives an application of standard econometric techniques in the form of a simultaneous econometric model for the Dutch economy. The model has to serve two ends: (i) it should give an adequate description of the structure of the Dutch economy, (ii) it should provide a procedure to predict the main economic variables for 1977.

Our study has been based on real data. Therefore the paper begins with a report on the collection of the postwar observations on the relevant variables. Furthermore, every stage in the construction of the model and the econometric methods used will be described carefully. This will result in the presentation of the predictions for 1977, while their associated margins of error are given in terms of the estimated standard deviations of the prediction errors.

The reader, who is only interested in the ultimate results, may turn to Subsection 5.3.
Dichotomous decisions based on dichotomously scored items: a case study
Authors: MELLENBERGH G. J. , KOPPELAAR H. , VAN DER LINDEN W. J.
Published: April 2008

In a course in elementary statistics for psychology students using criterion‐referenced achievement tests, the total test score, based on dichotomously scored items, was used for classifying students into those who passed and those who failed. The score on a test is considered as depending on a latent variable; it is assumed that the students can be dichotomized into the categories “mastery” (with scores on the latent variable above a cutting score), and “no mastery” (with scores below the cutting score on the latent variable). Two problems are considered: (a) How many students are classified incorrectly? Using the binomial error model a procedure is described for computing the classification proportions: p(mastery, passed), p(mastery, failed), p(no mastery, passed), and p(no mastery, failed), (b) What is the optimal cutting score on a test? Using a loss function a procedure for computing the optimal curring score is described.
Comparing approximations of confidence intervals for the product‐moment correlation coefficient
Authors: BOOMSMA A.
Published: April 2008

Five approximations in computing confidence intervals for the product‐moment correlation coefficient are compared. The α‐levels of the approximations are compared with three fixed nominal levels; for varying sample sizes and sample correlation values. It is recommended to use a method of RUBFN(or KRAEMER) [section 3d (3e)] for accurate approximations and a method of SAMIUDDIN[section 3b] for somewhat less accurate but quick results.
On a class of extensions to the Branley‐Terry model in paired comparisons
Authors: Baaren A. van
Published: April 2008

During the past decade a number of authors have proposed an extension to the basic Bradley‐Terry model for estimation from the results of paired comparison experiments.

The extension was either meant to accommodate ties in the individual comparisons or to estimate the effect of the order of presentation of the objects in these comparisons and, if necessary, to correct for the bias which may result from this effect. All the extensions have in common that, in order to achieve the objective, one or more parameters are added to the basic model. In this paper a class of extensions is presented of which the ones already published may be considered special cases. Some of the extensions from this class are compared and evaluated using a numerical example.
Distance between sampling with and without replacement
Authors: Stam A. J.
Published: April 2008

Summary Two random samples of size n are taken from a set containing N objects of H types, first with and then without replacement. Let d be the absolute (L1‐)distance and I the Kullback‐Leibler information distance between the distributions of the sample compositions without and with replacement. Sample composition is meant with respect to types; it does not matter whether order of sampling is included or not. A bound on I and d is derived, that depends only on n, N, H. The bound on I is not higher than 2I. For fixed H we have d0, I0 as N if and only if n/N0. Let Wr be the epoch at which for the r‐th time an object of type I appears. Bounds on the distances between the joint distributions of W1., Wr without and with replacement are given.