# Multiple Comparisons t-Test with Bonferroni Correction

The test statistic is:

where:

- and are the means of the two groups being compared and is the mean of the of groups,
- when applying the test to Repeated Measures, each respondent’s average is initially subtracted from their data and it is this corrected data that constitutes of ,
- is the number of observations in the th of groups,
- is the Calibrated Weight for the th observation in the group,
- is the Effective Sample Size for the group,
- for Repeated Measures and otherwise.
- ,
- the
*p*-value is then corrected as

## Circumstances when this test is applied

- Computing either:
- Column Comparisons
- A Planned Tests Of Statistical Significance for a row or column of a table.

- This test has been selected in the Statistical Assumptions setting of Multiple comparison correction > Column comparisons