In Exercise 10.6 we presented data on the estimated average price for a 6-ounce can or a 7.06-ounce pouch of tuna, based on prices paid nationally in supermarkets. A portion of the data is reproduced in the table below. Use the MINITAB printout to answer the questions.

Two-Sample T-Test and CI: Water, Oil
Two-sample T for Water vs Oil

Difference = mu (Water) - mu (Oil)
Estimate for difference: - 0.251
95% CI for difference: (-0.700, 0.198)
T-Test of difference = 0 (vs not =):
T-Value = -1.16 P-Value = 0.260 DF = 23
Both use Pooled StDev = 0.5389
a. Do the data in the table present sufficient evidence to indicate a difference in the average prices of light tuna in water versus oil? Test using α = .05.
b. What is the p-value for the test?
c. The MINITAB analysis uses the pooled estimate of σ2. Is the assumption of equal variances reasonable? Why or why not?

Transcribed Image Text:

Light Tuna in Water Light Tuna in Oil .99 .532.56 62 192 1411.92 1.23 1.12 1.30 62 85 63 .79 65 .65 67 23 60 69 60 60 66 67 Water 14 oil 11 Mean 0.896 1.147 StDev SE Mean 0.400 0.679 0.11 0.20