We illustrate the MINITAB commands and output for the two-sample r test. The approximate t test is performed if you don't click Assume equal variances.

Difference = mu (CI) - mu (C2)
Estimate for difference: -3.17
95% CI for difference:
(-7.61, 1.28)
T-Test of difference = 0 (vs not =): T-Value = -1.83
P-value = 0.127 DF = 5
Both use Pooled StDev = 2.2657
(a) From the output, what is the conclusion to testing H0: μ1, - μ2 = 0 versus a two-sided alternative at level α = .05?
(b) Refer to Table 12 of the Data Bank. Find a 97% confidence interval for the difference of mean monthly amount charged by the first and second age groups.

Data CI: 5283 C2:896 Dialog box Stat > Basic Statistics 2-Sample t Click Samples in different columns Type Cl in First. C2 in Second Click OK Click Assume equal variances Click OK Two-Sample T-Test and CI : C1, C2 Two- sample T for C1 vs C2 C1 4 4.50 C2 3 7.67 N Mean StDev SE Mean 1.3 0.88 2.65 1.53