De omvang van de steekproef bij een enkelvoudig steekproefsysteem

Summary  (Sample size for a single sampling scheme).
The operating characteristic of a sampling scheme may be specified by the producers 1 in 20 risk point ( p ₁), at which the probability of rejecting a batch is 0.05, and the consumers 1 in 20 risk point ( p ₂) at which the probability of accepting a batch of that quality is also 0.05.
A nomogram is given (fig. 2) to determine for single sampling schemes and for given values of p₁ and p ₂ the necessary sample size ( n ) and the allowable number of defectives in the sample ( c ).
The nomogram may reversedly be used to determine the producers and consumers 1 in 20 risk points for a given single sampling scheme.
The curves in this nomogram were computed from a table of percentage points of the χ² distribution. For v > 30 Wilson and Hilferty's approximation to the χ² distribution was used.     

Spatiotemporal characteristics and driving mechanisms of arable land in the Beijing-Tianjin-Hebei region during 1990-2015

This paper is an analysis of the spatiotemporal evolution characteristics of arable land in the Beijing-Tianjin-Hebei region from 1990 to 2015 and detects the driving factors of arable land change. On the basis of the study, the existing problems of arable land are discussed and some suggestions to promote regional rural development are proposed. The conclusions are as follows: (1) The proportion of arable land gradually decreased from 1990 to 2015 and the proportion of arable land in the south of the Beijing-Tianjin-Hebei region was larger than that in the north of the Beijing-Tianjin-Hebei region: arable land with a proportion of more than 75% lies in the low elevation and slope. The proportion of arable land in Beijing has also decreased faster than in other regions because most arable land was converted primarily into construction land due to urban expansion. (2) The mechanism showed that county economies and populations influenced the change in the quantity of arable land, and the position and natural conditions influenced the pattern changes in arable land. (3) Finally, this paper details some suggestions on the terms of legal institutions, the land consolidation project, and developing modern agriculture and industrial upgrading, which could provide scientific support for rural sustainable development and arable land protection in the Beijing-Tianjin-Hebei region.     

城市化进程中的农用地流转

从我国城市化进程和土地改革趋势以及坚守18亿亩耕地红线的背景入手,探讨了农用地流转与18亿亩耕地红线的关系。认为农用地流转可提高耕地利用效率,有助于促进耕地整理、复垦,增加耕地面积,有助于保障农民的权益。但农用地流转也会造成土地利用总体规划实施困难,存在强制流转等风险,针对此风险提出了构建农用地流转市场、加强土地流转监管等完善农用地流转机制的对策建议。     

城市耕地保护规模及对策研究——以长沙市为例

随着城市化进程的加快,我国城市规模也在迅速扩大,城市边缘区耕地在比较利益的驱动下成为建设用地扩张的主要目标。城市耕地保护规模的确定已成为控制建设用地扩张,缓解耕地非农化压力的关键。以长沙市为例,分析了耕地变化的特征,并采用粮食安全预测法对耕地保护的规模进行了测算,在此基础上,探讨了耕地保护的实现途径。     

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).     

中国城镇化过程中的土地利用问题及政策走向

中国是一个人口多人均耕地少的国家,随着经济的高速增长和城镇化的快速发展,土地资源的约束越来越突出.论文简述了中国在城镇化快速发展过程中的耕地保护和土地利用政策,分析了现阶段城镇化发展过程中存在的土地利用问题,探讨了当前和今后一个时期中国在土地利用与耕地保护方面的政策走向.     

我国耕地集约利用问题研究——以黑龙江省逊克县为例

耕地集约化利用则是当前我国人多地少、耕地面积和质量日益下降的时代背景下的必然要求和发展方向。本文以黑龙江省逊克县为例。从投入强度、产出效果、利用程度3方面构建了适合县域特征的耕地集约利用评价指标体系,从空间上对2006年逊克县各乡镇耕地集约利用差异性进行了综合评价。结果表明：逊克县在耕地集约利用方面取得了一些进步,但由于经济的快速发展,建设用地面积大幅增长,耕地非农化现象突出,农村劳动力将会逐步流向非农产业,导致耕地利用效率降低,同时由于自然灾害、水土流失、农业结构调整等原因,导致耕地资源数量和产出水平有明显降低,总体上各乡镇耕地集约利用水平不高。为了进一步提高逊克县耕地利用的集约水平,必须从加强农业基础设施建设、用地结构优化以及增加农业投入等几个方面加强管理。     

天津市二次调查中边缘化耕地分析及探讨

本文以天津市二次调查中耕地认定过程存在模糊的土地作为研究对象,将不稳定和可调整的耕地列入边缘化耕地范畴。通过对全市边缘化耕地的类别、数量和分布情况等进行分析和研究,首次摸清全市边缘化耕地家底,为天津市耕地保护、耕地占补平衡、耕地后备资源补充等土地资源管理和土地参与宏观调控提供决策依据。     

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.     

Investment committees and corporate cash holdings

We investigate the association between the voluntary formation of a board investment committee (IC) and corporate cash holdings for a large sample of Gulf Cooperation Council (GCC) firms over the 2005–2013 period. We provide evidence that the existence of a specialized IC increases corporate cash holdings. We also find that several IC characteristics, i.e., member experience, independence, number of meetings, and committee size, are associated with an increase in firms’ cash holdings. Furthermore, the local and foreign institutional ownership of GCC firms moderates the IC-cash holdings relationship. These results remain robust to alternative specifications of cash holdings and endogeneity tests. We contribute to the literature on firms’ incentives to hold cash and to the literature on governance in emerging market contexts.     

浅析青海土地开发整理项目中存在的问题和对策

土地开发整理项目是通过对项目区的综合整治,提高耕地质量和种植条件来促进地域经济的发展。文章以青海东部黄河谷地百万亩土地开发整理重大项目为例,对青海土地开发整理项目中存在的问题进行了分析,并就应对措施提出了一些见解。     

De invloed van de keuze der gewichten op de hoogte van een gewogen indexcijfer

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.     

Over correlatierekening en de herleiding van klimatologische reeksen

Summary  (A useful climatological application of regression theory) It is often required to estimate the 24th mean temperature from a few known temperatures, e.g. at 8h, 14h and 19h, when a sample of accurately known 24h means is available. The usual method is to add a constant to the mean of the three temperatures.
It is better however to compute a regression equation of the accurate 24h means on the three temperatures.
An example is given, showing that the efficiency of the regression method is about 6 times as great as that of the usual method.     

Over de spreiding bij het droge-stofonderzoek van brood

The accuracy of the determination of the amount of solids in bread.
Of a loaf with a nominal weight of 800 grams only about 480 grams remains after complete drying. This so-called 'amount of solids in bread' is regularly checked by samples. From a batch of loaves a group of at least 5. but usually more, are taken at random and weighed. From this group one is selected with a weight as nearly as possible equalling the average weight of the whole group; for two slices of this sample loaf the decrease in weight upon drying is determined in the laboratory, and is considered as representative for the entire batch.
The accuracy of these determinations is analysed on the basis of 35 samples which were investigated in 3 different laboratories. The standard error is estimated at 5 grams per loaf. The influence of various factors, such as the method of sampling which may be altered in many ways, is briefly considered, while in a final section the results obtained are discussed from a practical point of view.     

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.     

Het probleem van de ruïnering der spelers

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.     

Bepaling van de personeelssterkte op kostenbasis*

Determining the optimal number of staff in a department using a method based on costs. How many men do you appoint in a department of a firm? This number can be determined in an optimal way, if the following data are known: - The number of men required per unit of time (may be given as a stochastic quantity). - The mean probability of absence per man in the department (due to illness, holidays etc.). - Wages per man. - Costs (proceeds), if in one unit of time there are less (more) men available than required. Generally the solution will be obtained by an iterative method. However, when the parameters show a certain behaviour it is possible to find the optimum solution by analytical and graphical means.     

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.     

Het oordeel van een bedrijfsleider over de toepassing van de statistiek in het bedrijf

A manager's view on the application of statistics in the concern.
To be able to judge of the correct dosing of statistical methods in his concern a manager should discriminate between incidental research and systemetical application of statistics. A sound job limitation and good information are indispensable to the success of a statistical check system.
The cost of the introduction of statistical check methods into a concern with a variated manufacturing programme in the field of electrical engineering (350 people) was estimated to be Djls 18,000 in one year. In the next year more than this amount will be earned back through the savings and the improvements obtained.