The accompanying data consists of prices ($) for one sample of California cabernet sauvignon wines that received ratings of 93 or higher in the May 2013 issue of Wine Spectator and another sample of California cabernets that received ratings of 89 or lower in the same issue.

Assume that these are both random samples of prices from the population of all wines recently reviewed that received ratings of at least 93 and at most 89, respectively.
a. Investigate the plausibility of assuming that both sampled populations are normal.
b. Construct a comparative boxplot. What does it suggest about the difference in true average prices?
c. Calculate a confidence interval at the 95% confidence level to estimate the difference between µ1, the mean price in the higher rating population, and µ2, the mean price in the lower rating population. Is the interval consistent with the statement "Price rarely equates to quality" made by a columnist in the cited issue of the magazine?

Transcribed Image Text:

2 93: 100 100 60 135 195 195 125 135 95 4275 72 s 89: 80 75 75 85 75 3585 65 45 100 28 38 50 28