The following results are for independent random samples taken from two populations. Sample 1 Sample 2 n1 = 20 n2 = 30 x1 = 22.6 x2 = 20.1 s1 = 2.6 s2 = 4.8 (a) What is the point estimate of the difference between the two population means? (Use x1 − x2. ) 2.5 (b) What is the degrees of freedom for the t distribution? (Round your answer down to the nearest integer.) 48 (c) At 95% confidence, what is the margin of error? (Round your answer to one decimal place.) (d) What is the 95% confidence interval for the difference between the two population means? (Use x1 − x2. Round your answers to one decimal place.)