A sample of ten yields the following data:

x 10 8 11 7 10 11 6 7 15 9 y 103 85 115 73 97 102 65 75 155 95

a. Provide a 95% confidence interval for the average y when xp = 9.4.

b. Provide a 95% confidence interval for the average y when xp = 10.

c. Obtain the margin of errors for both part a and part

b. Explain why the margin of error obtained in part b is larger than that in part a.

14-40. A regression analysis from a sample of 15 produced the following:

1xi - x21yi - y2 = 156.4

1xi - x22 = 173.5

1yi - y22 = 181.6

1yi - yn22 = 40.621 x = 13.4 and y = 56.4

a. Produce the regression line.

b. Determine if there is a linear relationship between the dependent and independent variables. Use a significance level of 0.05 and a p-value approach.

c. Calculate a 90% confidence interval for the amount the dependent variable changes when the independent variable increases by 1 unit.

Business Applications