Problems Arising in the Analysis of a Series of Similar Experiments

Abstract

An efficient type of modern field experiment is that in which a replicated trial is laid down in the same year at a number of centres, or carried out at the same centre independently throughout a number of years. The statistical problems which arise in the interpretation of the results of such a set of data are of wide generality. For any treatment effect, we obtain at each centre an estimate x and an estim- ate s of its standard error, based on n degrees of freedom. As a preliminary to more detailed examination, the experimenter wants to estimate and test the significance of the mean treatment effect and to find whether it has varied from centre to centre.