A statistics instructor wanted to see if student participation in review preparation methods led to higher examination scores. Five students were randomly selected and placed in each test group for a three-week unit on statistical inference. Everyone took the same examination at the end of the unit, and the resulting scores are shown below. Is there sufficient evidence at α = 0.05 to conclude an interaction between the two factors? Is there sufficient evidence to conclude a difference in mean scores based on formula delivery system? Is there sufficient evidence to conclude a difference in mean scores based on the review organization technique?

Formulas provided 89, 76, 80, 90, 75 75, 80, 68, 65, 79 Student-made formula cards 94, 86, 80, 79, 82 88, 78, 85, 65, 72 Student-led review Instructor-led review