Two independent samples have been selected, 7676 observations from population 1 and 6363 observations from population 2. The sample means have been calculated to be x1=10.8x1=10.8 and x2=6.8x2=6.8. From previous experience with these populations, it is known that the variances are 21=2512=25 and 22=2022=20.

(a) Find (x1x2)(x1x2). answer: ____________________

(b) Determine the rejection region for the test of H0:(12)=2.87H0:(12)=2.87 and Ha:(12)>2.87Ha:(12)>2.87 Use =0.02=0.02. z>_________________

(c) Compute the test statistic. z=______________________

The final conclustion is (which of the below?)

A. There is not sufficient evidence to reject the null hypothesis that (12)=2.87(12)=2.87. B. We can reject the null hypothesis that (12)=2.87(12)=2.87 and accept that (12)>2.87(12)>2.87.

(d) Construct a 9898 % confidence interval for (12)(12). _________________ (12) (12) ___________________