Consider the following values for the dependent and independent variables:
x y
5…………………….10
15…………………...15
40…………………...25
50…………………...44
60…………………...79
80…………………..112
a. Develop a scatter plot of the data. Does the plot suggest a linear or nonlinear relationship between the dependent and independent variables?
b. Develop an estimated linear regression equation for the data. Is the relationship significant? Test at an α = 0.05 level.
c. Develop a regression equation of the form  = b0 + b1 x + b2 x2. Does this equation provide a better fit to the data than that found in part b?