Use the traditional method to test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected. Select the appropriate response. With separate lines at the checkouts, a store manager finds that the standard deviation for the waiting times on Monday mornings is 5.7 minutes. After switching to a single waiting line, he finds that for a random sample of 29 customers the waiting times have a standard deviation of 4.9 minutes. Use a 0.025 significance level to test the claim that with a single line, waiting times vary less than with separate lines. Select the correct test statistic and critical value.
Test statistic: x^2 = 18.462. Critical value: x^2 = 15.308
Test statistic: x^2 = 20.692. Critical value: x^2 = 15.308
Test statistic: x^2 = 20.692. Critical value: x^2 = 7.815, 15.308
Test statistic: x^2 = 18.462. Critical value: x^2 = 7.815, 15.308