Unformatted text preview: than 1.96. Question 3: We have n = 40 , ¯ x = 2 . 31 ,s = 6 . 92. a. The required CI is 2 . 31 ± 2 . 575 6 . 92 √ 40 ⇔ (. 51 , 5 . 13). b. Based on the given data, with 99% conﬁdence, the mean gain in weight is between losing 0.51 pounds to gaining 5.13 pounds. c. Since 0 is in the 99% CI, with 99% conﬁdence, the program is not eFective. d. The width of the 95% CI is 2(1 . 96) 6 . 92 √ 40 = 4 . 2891. Question 4: Let X be the placebo and Y be the aspirin group. Then n = 684 ,x = 28 ,m = 676 ,y = 18 and also ˆ p X = 0 . 0409 , ˆ p Y = 0 . 0266. a. The required CI for p Xp Y is (0 . 0409. 0266) ± 1 . 96 q . 0409(1. 0409) / 684 + 0 . 0266(1. 0266) / 676 ⇔ (. 0049 , . 0335) b. With 95% conﬁdence, the diFerence is 0.59% (asiprin higher) to 4.45% (placebo higher). c. Since 0 is in the 95% CI, no evidence that aspirin treatment is eFective....
View
Full Document
 Spring '10
 AugustineWong
 Math, 0.51 pounds

Click to edit the document details