Question

In order to compare the means of two populations, independent random samples of 220 observations are selected from each population, with the following results: Sample 1 Sample 2 ?⎯⎯⎯1=0 ?⎯⎯⎯2=5 ?1=165 ?2=200

(a) Use a 97 % confidence interval to estimate the difference between the population means (?1−?2). ≤(?1−?2)≤

(b) Test the null hypothesis: ?0:(?1−?2)=0 versus the alternative hypothesis: ??:(?1−?2)≠0. Using ?=0.03, give the following: the test statistic ?= The final conclusion is:

A. There is not sufficient evidence to reject the null hypothesis that (?1−?2)=0.

B. We can reject the null hypothesis that (?1−?2)=0 and conclude that (?1−?2)≠0.

(c) Test the null hypothesis: ?0:(?1−?2)=20 versus the alternative hypothesis: ??:(?1−?2)≠20. Using ?=0.03, give the following: the test statistic ?=

The final conclusion is

A. We can reject the null hypothesis that (?1−?2)=20 and conclude that (?1−?2)≠20.

B. There is not sufficient evidence to reject the null hypothesis that (?1−?2)=20.

Answer 1

0-2 ± 2.13 116 2002 220220 -2. ±(2.17),17.41, 2 ± 37.93 -- 39.13 , 35.13 2-20 22-0 ConclusimA 0-2-20 2o02 ㄣ 22-0 22