What is the Bonferroni adjustment What would the Bonferroni

What is the Bonferroni adjustment? What would the Bonferroni adjustment be for a study with four groups for which a researcher decided to use t-tests?

Solution

What is the Bonferroni adjustment? What would the Bonferroni adjustment be for a study with four groups for which a researcher decided to use t-tests for comparisons with a = .05?

The Bonferroni correction can be used to control the familywise error rate. If we want the familywise error rate to be , you use /c as the per-comparison error rate. c is the number of comparisons made. This correction, called the Bonferroni correction, will generally result in a familywise error rate less than .

For four groups , number of comparisons are n(n-1)/2 =4*3/2=6

adjusted alpha level =0.05/6=0.0083