1. Consider the following data for two variables, x and y.

x 22 24 26 30 35 40 y 12 21 33 35 40 36

a. Develop an estimated regression equation for the data of the form yˆ = b0 + b1x.

b. Use the results from part

(a) to test for a significant relationship between x and y.

Use a = .05.

c. Develop a scatter diagram for the data. Does the scatter diagram suggest an estimated regression equation of the form yˆ = b0 + b1x + b2x2? Explain.

d. Develop an estimated regression equation for the data of the form yˆ = b0 + b1x +

b2x2.

e. Refer to part (d). Is the relationship between x, x2, and y significant? Use a = .05.

f. Predict the value of y when x = 25.