Showing papers in "Biometrika in 1933"
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TL;DR: In this article, the significance of the difference between correlation coefficients, r1 and r2, found in two independent samples of size n1 and n2, was considered as that of testing the hypothesis that the samples have been drawn from populations in which the coefficients of correlation between the variables have some common, but unspecified value, p.
Abstract: THE problem of testing the significance of the difference between correlation coefficients, r1 and r2, found in two independent samples of size n1 and n2 may be considered as that of testing the hypothesis that the samples have been drawn from populations in which the coefficients of correlation between the variables have some common, but unspecified value, p. A method of procedure commonly used, which is adequate if the samples are large and p not too near either + I or 1, is to compare the difference, r1 r2, with an estimate of its standard error, 0'rl-1'2 But if these conditions are inot satisfied, we are at once faced with certain difficulties: (a) the value of o>,j-r2 is very sensitive to the particular estimate of p chosen; (b) the sampling distribution of r1 92 will be asymnietrical, difficult to calculate and again dependent on the estimlate of p.
TL;DR: In this article, the authors considered the problem of estimating the moment coefficients of a population with finite moments, and showed that the semi-invariants can be derived algebraically or more simply by following out certain straightforward combinatorial rules.
Abstract: THE appearance of yet another paper on the sampling problem* directs attention to the success which has attended of recent years the efforts of workers in this field. The general problem considered by one group of workers is the following. Let there be given a population, supposed infinite in extent, but subject to this having any law of distribution with finite moments. It may be a population of one or manv variables. The population may be regarded as completely specified by a knowledge of all its characteristic parameters, which may be moment coefficients or semi-invariants, or expressible in terms of these. For a sample of size n drawn at randomi fiom this population we may calculate in sonme manner certain ftunctions which are to be regarded as estimates of the population moment coefficients, or semii-invariants. The simiultaneous distribuition in repeated samples of the various estimates will depend upon that of the parent population, and the problem I wish to take up deals with the determinationi of the moment coefficients, or sei-ni-invariants, of this simultaneous distribution. Prior to 1928 certain individual results oinly had been worked out; in that year two independent papers of great importance appeared. R. A. Fishert showed that if we define as estimates of the population semi-invariants (ic,.) certain functionis (kr) of the sample observations by means of the simple propeity that the mean value of kr for an infinite number of samples is to be K4++, then the semi-invariants of the simultaneous distribution of the k's are peculiarly simnple in form, compared to analogouis expressions derived in other ways. These semi-invariants can be derived algebraically, or more simply by following out certain straightforward combinatorial rules. Fisher's paper marked a great advance in showing the possibility of beginning a systematic tabulation of the required formtulae, a thing that had not before been possible. In his paper all formulae up to the tenth degree were given, together with a numniber of special interest of the twelfth degree. In addition the paper showed how the methods could readily be applied to multivariate populations, and a number of the more general fornmulae were given.
TL;DR: The history of multiple births in three generations of a family, tranismitted, in the particular case under his observation, through a male, III.
Abstract: (1) SOME two years ago, Dr E. A. Barton, working in coninection with the Obstetric Department of University College Hospital, came across an interesting history of plural births in three generations of a family, tranismitted, in the particular case under his observation, through a male, III. 10, who was believed himself to have been a single birth. Mvr Herbert Spencer warns us* that statistics of patients treated in lying-in-wards are alone reliable in respect of iiiultiple births, as one of a twinship often dies and the fact of a twin pregnancy may not be imientioned to the patient. However, their history of multiple births has been of interest, not unaccompanied by anxiety, in the famnily whose pedigree is given under Fig. 1, and so far as his mother and his grandimother wvere aware, III. 10 was born at a single birth.