Study Questions:
Is eating oat bran an effective way to reduce cholesterol? Early studies indicated that eating oat bran daily reduces cholesterol levels by 5% to 10%. Reports of this study resulted in the introduction of many new breakfast cereals with various percentages of oat bran as an ingredient. However, an experiment performed by medical researchers in Boston cast doubt on the effectiveness of oat bran. In that study, 120 volunteers ate oat bran for breakfast, and another 120 volunteers ate another grain cereal for breakfast. At the end of 6 weeks, the percentage of cholesterol reduction was computed for both groups. Can we infer that oat bran is different from other cereals in terms of cholesterol reduction?
Test to determine whether conservatives and liberals differ in the amount of education (EDUC).
Estimate with 95% confidence the difference in the amount of education (EDUC) between American-born and foreign-born residents.
A statistics practitioner conducted a two-factor analysis of variance experiment with a = 4, b = 3, and r = 8. The sums of squares are listed here:
SS(Total) = 9420 SS(A) = 203 SS(B) = 859 SS(AB) = 513
a. Test at the 5% significance level to determine whether factors A and B interact.
b. Test at the 5% significance level to determine whether differences exist between the levels of factor A.
c. Test at the 5% significance level to determine whether differences exist between the levels of factor B.