# Question

As mentioned in Exercise 10.31, Quadro Corporation has two supermarkets in a city. The company’s quality control department wanted to check if the customers are equally satisfied with the service provided at these two stores. A sample of 380 customers selected from Supermarket I produced a mean satisfaction index of 7.6 (on a scale of 1 to 10, 1 being the lowest and 10 being the highest) with a standard deviation of .75. Another sample of 370 customers selected from Supermarket II produced a mean satisfaction index of 8.1 with a standard deviation of .59. Assume that the customer satisfaction index for each supermarket has an unknown and different population standard deviation.

a. Construct a 98% confidence interval for the difference between the mean satisfaction indexes for all customers for the two supermarkets.

b. Test at a 1% significance level whether the mean satisfaction indexes for all customers for the two supermarkets are different.

c. Suppose that the sample standard deviations were .88 and .39, respectively. Redo parts a and b. Discuss any changes in the results.

a. Construct a 98% confidence interval for the difference between the mean satisfaction indexes for all customers for the two supermarkets.

b. Test at a 1% significance level whether the mean satisfaction indexes for all customers for the two supermarkets are different.

c. Suppose that the sample standard deviations were .88 and .39, respectively. Redo parts a and b. Discuss any changes in the results.

## Answer to relevant Questions

Refer to Exercise 10.32. As mentioned in that exercise, according to the credit rating agency Equifax, credit limits on newly issued credit cards increased between January 2011 and May 2011. Suppose that random samples of ...Perform the following tests of hypotheses, assuming that the populations of paired differences are normally distributed. a. H0: µd = 0, H1: µd ≠ 0, n = 9, = 6.7, sd = 2.5, α = .10 b. H0: µd = 0, H1: µd > 0, n = 22, ...A factory that emits airborne pollutants is testing two different brands of filters for its smokestacks. The factory has two smokestacks. One brand of filter (Filter I) is placed on one smokestack, and the other brand ...Refer to the information given in Exercise 10.61. Test at a 2% significance level if p1 is greater than p2. n1 = 100, p̂1 = .81, n2 = 150, p̂2 = .77 The lottery commissioner’s office in a state wanted to find if the percentages of men and women who play the lottery often are different. A sample of 500 men taken by the commissioner’s office showed that 160 of them ...Post your question

0