posted by peter .
(a)Comparison of GPA for randomly chosen college juniors and seniors:
xbar= 3.05, s1 = .20, n1 = 15, xbar2= 3.25, s2 = .30, n2 = 15, á = .025, left-tailed test.
Standard error ____________
This looks like an independent groups t-test.
Here are a few hints:
1. d.f. for an independent groups t-test is this: n1 + n2 - 2
2. Use the denominator of the appropriate t-test as the standard error of the difference between the two means.
3. Use the appropriate t-test to calculate the t-test statistic.
4. P-value is the actual level of the t-test statistic (found using a t-table).
5. T-critical can be found using a t-table with the appropriate degrees of freedom for a one-tailed test.
I hope this will get you started.