Refer to Exercise 13.48. Suppose we are missing the following observations: y = 33, 28, 10.
a. Fit the model y = β0 + β1x + β2x2 + ɛ.
b. Test for lack of fit, using α = .05.
c. Again examine the residuals.
In exercise
y, Solubility by Weight x, Temperature (° C)
43, 45, 42…………………………………… 0
32, 33, 37………………………………….. 25
21, 28, 29………………………………….. 50
15, 14, 9…………………………………… 75
12, 10, 8………………………………….. 100
7, 6, 2…………………………………….. 125