摘要:

SummaryA method of quality control during production.This paper describes the use of control charts in general, and of the control charts for percentage defectives in particular. A discussion of the principles of the control charts and of methods to fix the sample size, the sample frequency, and the warning and stop lines is followed by practical hints concerning the use of the charts and their introduction in the factory. The necessity of computing the average percentage defective from the total number of defectives recorded in a series of successive samples is emphasized. It is also pointed out that an analysis of the frequency of the numbers of defectives found in the samples can sometimes furnish useful information regarding the trustworthyness of the inspector.

ISSN:0039-0402    

DOI:10.1111/j.1467-9574.1949.tb00396.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

SummaryCriticisms against the ‘Hyperbolic Error Distribution’.In a previous article in this journal(Vol. 1, p. 55, 1948)the hyperbolic error distributionwas derived by theoretical argument, starting from simple hypotheses. Against this derivation criticisms have been raised from various sides. These are answered in the present paper.Though it is on the one hand acknowledged that an error has slipped into the previous arguments, it is on the other hand maintained that the hyperbolic distribution can be held upright on a slightly altered basis, namely on a set of approximate, instead of exact, equations.In a postscript the editors point out that serious objections can be raised against these altered vi

ISSN:0039-0402    

DOI:10.1111/j.1467-9574.1949.tb00397.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

SummaryAn experiment on estimation.On ten pieces of card board a line was drawn 100 mm in length and divided by a vertical dash (the pointer) in two parts, in each case at a different point. 40 persons were asked to estimate the length of the left hand portion after they had been told that the total length was 100 mm. The problem discussed is how to decide which person is the ‘best’ estimator.Three criteria are proposed: (I) the sum of the absolute values of the deviations; (II) a similar weighted sum, each deviation being multiplied with the inverse of its standard deviation, in order to account for the obvious differences in accuracy for different positions of the pointer; and (III) by adding for each of the ten readings of one person the proportions of the observers whose readings were worse. Applied to a set of four observers all three criteria indicate No. 20 as the ‘best’ and No. 5 as the ‘worst’. If however we judge the observers by their mutual correlation coefficients, according to a method of Spearman, No. 20 turns out to be the worst.Hence in applying Spearman's criterion caution seems required. It is pointed out that there does not as yet exist a universally recognized and accepted method for determining the relative quality of a set o

ISSN:0039-0402    

DOI:10.1111/j.1467-9574.1949.tb00398.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Book reviewed in this article:Econometrie door J. Tinbergen

ISSN:0039-0402    

DOI:10.1111/j.1467-9574.1949.tb00399.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY