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A USA based cable broadband company wants to compare the average customer satisfaction scores between its east coast and west coast customer bases. The customer survey asks for a score between 1 and 5, with 1 being poor and 5 being excellent. 174 east coast customers are surveyed, and the sample mean is 3.51 with a sample standard deviation (s) of 0.51. For the west coast, 355 customers are surveyed, and the sample mean is 3.24 with a sample standard deviation (s) of 0.52.

a. Create a 95% confidence interval for the true average score forwest coast customers.

What is the UPPER limit of the confidence interval?

Round to the nearest 3rd decimal place, x.xxx

b. Now say you consider the difference between the average scores between west coast and east coast. Say you do west coast average minus east coast average.

Create a 95% confidence interval for the difference in average scores(west coast minus east coast).

What is the UPPER limit of the confidence interval?

Round to the nearest 3rd decimal place, x.xxx. If upper limit is negative, make sure to include a negative sign, -x.xxx