Question

We want to compare the heights of Marines at Camp Pendleton and Camp Lejeune. From a random sample of 15 individuals from Camp Pendleton, we have sample mean xbar_P = 68 and sample standard deviation s_P = 3. From a random sample of 11 individuals from Camp Lejeune, we have sample mean xbar_L = 70 and sample standard deviation s_L = 4.
(a) Calculate a two-sided 90% confidence interval for the mean height of Marines at Camp Pendleton. 

(b) We want to examine whether the mean heights differ between these two locations. State the null and alternative hypotheses. 

(c) Suppose we believe the variances of the two populations are equal. Compute the pooled variance estimate, the test statistic, and the P -value. 

(d) Suppose there is no reason to believe the variances of the two populations are equal. Compute the test statistic and the P -value. 


Answer 1