Assumptions for the usual two sample t test
Enumerating a small permutation distribution
Example: 2 students were randomly assigned to a new reading program, 3 were randomly assigned to the usual reading program. Over winter break, the number of books read were 7 and 15 from the new group, versus 2, 4, and 8 from the old group. What were all the possible ways that their books read could have been distributed among the two groups?
|New group||Old group||New group mean||Old group mean||Mean difference|
Let's examine the permutation distribution of the mean differences.
The permutation principle: The permutation distribution is an appropriate reference distribution for conducting inference (calculating p values, determining the significance of tests). Permutation distributions lead to exact tests.
Equivalence of other statistics, summary of steps in a permutation test.
Hypotheses tested in a two sample permutation test
Basing a permutation test on other sample statistics, such as the median or trimmed mean.