Expected values of discrete random variables and elementary statistics

the long version

This short work can Only enhance Professor Edwards' reputation as an accomplished writer on statistical methods. Here he treats of the some- what abstruse subject of statistical expectation in a simple, lucid manner, readily comprehensible to the reader with little or no background in mathematical statistics. Hence, sociologists seeking greater insight into the logic of statistical procedures which they may mechanically apply will find this volume a fruitful source and reference. As the title connotes, the contents consist largeIy of the expectations of elementary averages, such as the mean, the variance, and the covariance. The importance of these results in this writing lies not in their rudimentary character, however, but rather in their capacity to illustrate the concept of statistical expectation and to suggest its analytical utility. Thus, the comparison of expected mean squares for treatments in a two-way analysis of variance under varying sampling conditions, is instructive as regards the selection of a valid error term in the variance ratio. Analogously, the validity of such common nonparametric methods as the Mann-Whitney test is clarified by the derivation of the expectation of the sum of a set of N ranks.