Summary of t-Test

• There are two kinds of t-tests: independent and correlated.
• Correlated t-tests use paired observations on one group of subjects. This is called a within-subjects design.
• Independent t-test use subjects which have been randomly-assigned to two groups.
• The degrees of freedom for a correlated t-test equals n-1.
• The degrees of freedom for an independent t-test equals N-2.
• T-tests are not used with more than two groups because of the likelihood of Type I error.
• T-tests measure the differences between means.
• T-tests are like z-scores.
• The independent t-test pools the variance of the subgroups.

NOW YOU CHOOSE:
    Day 8: Student’s t-Test
    Bit More About t-Test
    Even More About t-Test
    How to Calculate t-Test
    Practice Problems
    More Practice Problems
    Word Problems
        Sim1           Sim2            Sim3
        Sim4           Sim5            Sim6
        Sim7           Sim8            Sim9
    Basic Facts About t-Test
    Vocabulary
    Formulas
    Quiz 8
    Summary