Different tests for a difference: How do we do research?

摘要

Most biological scientists conduct experiments to look for effects,and test the results statistically. We have already described Student’st-test which is very commonly used. However, this testconcentrates on a very limited question. We assume that there isno effect in the experiment, and then estimate the possibility thatwe could have obtained these results. The question concerns whatwe may deduce, if the samples measured came from a single theoreticalpopulation of known characteristics. We calculate theprobability that we might obtain the results we did, or moreextreme results, on the basis of this premise. The statistical procedureis called frequentist because the results are expressed interms of ‘how frequently would a result like this be observed,given the exact definition of the theoretical population that weproposed?’ (Fig. 1).