2. t-test 1-sample t-test or correlated-sample t-test or paired-sample t-test 2-sample t-test or independent-sample t-test or unpaired-sample t-test compare the mean of the difference between 2 groups of data compare the difference of the mean of 2 groups of data

3. Group 1Group 2difference 812- 4 1015- 5 1218-6-6 Mean ± SD10 ± 215 ± 3- 5 ± 1 Example of t-test: t-test 2-sample t-test 1-sample t-test compare: 10 ± 2 versus 15 ± 3 - 5 ± 1 versus 0

4. 1-sample t-test: compare the mean of the difference... H o : Δ X = 0 {for 2-tail p-value} H a : Δ X ≠ 0 test statistic: and

5. 1-sample t-test: compare the mean of the difference... H o : Δ X ≥ 0 {for 1-tail p-value} H a : Δ X < 0 test statistic: and

6. 2-sample t-test: compare the difference of the mean... H o : X 1 = X 2 {for 2-tail p-value} H a : X 1 ≠ X 2 test statistic: at n 1 = n 2 = n, SD 1 = SD 2, and Δx = {it’s similar to the test statistic for the 1-sample t-test} and

7. 2-sample t-test: compare the difference of the mean... H o : X 1 ≤ X 2 {for 1-tail p-value} H a : X 1 > X 2 test statistic: at n 1 = n 2 = n and Δx = {it’s similar to the test statistic for the 1-sample t-test} and