A geneticist is studying the influence of gene aP2 on diabetes. She measures the level of insulin (in ng/ml) in a random sample of 20 normal mice and finds their mean = 30 and SD = 9. In another random sample of 15 mice whose gene aP2 is removed, the mean =27 and SD = 8. Assume that the insulin levels vary according to normal distribution with equal variances. Which of the following is used for the SE of the difference in the mean insulin levels between the normal mice and aP2 removed mice? Oa. so , where so is the pooled variance. Ob. 1 1 So X 20 15 : where So is the pooled variance. O c. 92 82 20 15 Od. 92 82 2x 20 15(Continuation) Compute the ME of the 95% CI for the difference in the mean insulin levels of the two groups. O a. 1 1 t 33,0.975 XSp X + 20 15 , where spy sp2 is the pooled variance. Ob. 1 1 t 35,0.975 XSX + 20 15 , where sp sp2 is the pooled variance. O c. 1 1 tv.0.975 XSp X 20 + 15 , where v is given by Sattherwaite's approximation. Od. 92 82 2x1 + 20 15(Continuation) Suppose the 95% Cl found above is (3, 9). Do you conclude that the two mice groups differ in terms of the average insulin levels with 95% confidence? a' Yes, because 0 is included in the Cl. b- No, because 0 is included in the Cl. C' Yes, because the difference in averages, 3, is positive. / \\ d- No, because the difference in averages, 3, is positive