| Abstract: | I compared the randomization/permutation test and theF test for a two-cell comparative experiment. I varied (1) the number of observations per cell, (2) the size of the treatment effect, (3) the shape of the underlying distribution of error and, (4) for cases with skewed error, whether or not the skew was correlated with the treatment. With normal error, there was little difference between the tests. When error was skewed, by contrast, the randomization test was more sensitive than theF test, and if the amount of skew was correlated with the treatment, the advantage for the randomization test was both large and positively correlated with the treatment. I conclude that, because the randomization test was never less powerful than theF test, it should replace theF test in routine work. |
