Textbook Problem

The following results are for independent random samples taken from two populations.

Sample 1	Sample 2
n1 = 20	n2 = 30
${\bar{x}}_{\text{1}}=\text{2}2.5$	${\bar{x}}_{\text{2}}=\text{2}0.\text{1}$
s1 = 2.5	s2 = 4.8

1. a. What is the point estimate of the difference between the two population means?
2. b. What is the degrees of freedom for the t distribution?
3. c. At 95% confidence, what is the margin of error?
4. d. What is the 95% confidence interval for the difference between the two population means?