Waiting time for checkout line at two stores of a supermarket chain were measured for a random sample of customers at each store.

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1. What are the null and alternative hypothesis for this research?
2. What are the sample mean waiting time for checkout line and the sample standard deviation for the two stores?
3. Compute the test statistic t used to test the hypothesis. Note that the population standard deviations are not known and therefore you cannot use the formula in Section 10.1. Use the one in Section 10.2 instead.
4. Compute the degree of freedom for the test statistic t.
5. Can the chain conclude that the mean waiting time for checkout at Store 1 is lower than that of Store 2? Use the critical-value approach and α = 0.05 to conduct the hypothesis test.
6. Construct a 95% confidence interval for the difference of mean waiting time for checkout line at the two stores.