TRUE OR FALSE.

1. You can only use paired t-test when the data are in pairs.

2. When testing cause-and-effect, the independent variable is traditionally plotted on the Y axis, while the effect is plotted it on the X axis.

3. Under the null hypothesis that observations in different groups have the same mean, the weighted between-group variance will be the same as the within-group variance.

4. Welch t-test is slightly more powerful than two-sample t-test when SD are equal but is not when the SD among the two groups are very unequal.

5. There are several statistical tests that use the t-distribution and can be called a t-test.

6. One-sample t test elucidates the difference between sample and population mean in units of standard error (SE).