Can I use multiple t tests?
Every time you conduct a t-test there is a chance that you will make a Type I error. By running two t-tests on the same data you will have increased your chance of “making a mistake” to 10%. The formula for determining the new error rate for multiple t-tests is not as simple as multiplying 5% by the number of tests.
Why is it inappropriate to use multiple t tests in an experiment with more than two groups?
It is inappropriate because the repetition of the multiple tests may repeatedly add multiple chances of error, which may result in a larger α error level than the pre-set α level.
How do I report multiple t tests?
In the Analysis tab of Preferences, choose either to always report P values in scientific format, or at least to report tiny P values in scientific format. In the parameters dialog for the multiple t test analysis, choose to report P values with N digits after the decimal and enter a large value for N.
How is a t test used to analyze differences between groups?
The following statistical tests are commonly used to analyze differences between groups: A t-test is used to determine if the scores of two groups differ on a single variable. A t-test is designed to test for the differences in mean scores.
What happens when you run two t tests?
By running two t-tests on the same data you will have increased your chance of “making a mistake” to 10%. The formula for determining the new error rate for multiple t-tests is not as simple as multiplying 5% by the number of tests.
When to use a t test in school?
A t-test is used to determine if the scores of two groups differ on a single variable. A t-test is designed to test for the differences in mean scores. For instance, you could use a t-test to determine whether writing ability differs among students in two classrooms. Note: A t-test is appropriate only when looking at paired data.
Which is the best two sample t test?
Other multiple comparison methods include the Tukey-Kramer test of all pairwise differences, analysis of means (ANOM) to compare group means to the overall mean or Dunnett’s test to compare each group mean to a control mean. What if the variances for my two groups are not equal? You can still use the two-sample t- test.