lists the performance scores BEFORE and AFTER these interventions.

(a) Calculate mean performance scores in each group before the intervention. Then calculate the mean difference. Is this mean difference based on paired or independent samples?

(b) Within group 1 (individuals 1 through 3), calculate the difference in scores from after to before the intervention (AFTER minus BEFORE). Then calculate the mean difference. Is this mean difference based on paired or independent samples?

(c) Within group 2 (individuals 4 through 6), calculate changes in scores (AFTER minus BEFORE). What is the mean difference in these scores?

(d) Compare mean improvements in the two groups. Is this a paired or independent comparison?