# Question: Refer to Exercise 10 28 Now assume that the two populations

Refer to Exercise 10.28. Now assume that the two populations are normally distributed with unequal and unknown population standard deviations.

In Exercise 28

a. Make a 90% confidence interval for the difference between the corresponding population means.

b. Test at a 5% significance level whether the two population means are different.

c. Suppose that the sample standard deviations were 9.5 and 5.1 hours, respectively. Redo parts a and b. Discuss any changes in the results.

In Exercise 28

a. Make a 90% confidence interval for the difference between the corresponding population means.

b. Test at a 5% significance level whether the two population means are different.

c. Suppose that the sample standard deviations were 9.5 and 5.1 hours, respectively. Redo parts a and b. Discuss any changes in the results.

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