Two random samples from Normal populations with equal varian

Two random samples from Normal populations with equal variances yield: n_1= 15, n_2 = 17, s_p^2 = 3.7. If a 2-sided confidence interval for mu_1 - mu_2 is (-1.8563, 0.4563), what is an estimate of mu_1 - mu_2? Two random samples from Normal populations with unequal variances yield: n_1= 16, n_2 = 18, s_1 = 3.7, s_2 = 4.5. What are the degrees of freedom (df) V associated with hypothesis tests and Cls for mu_1 - mu_2? (Same information as #1 above. You better get that problem right!) Two random samples from Normal populations with equal variances yield: n_1= 15, n_2 = 17, s_p^2 = 3.7. If a 2-sided confidence interval for mu_1 - mu_2 is (-1.8563, 0.4563), what is a 95% lower confidence bound for mu_1 - mu_2?

Solution

question 1) ans is (b) at 5% level of significance