# Question: Refer to the data of Exercise 13 44 a Can we test

Refer to the data of Exercise 13.44.

a. Can we test for lack of fit for the following model?

y = β0 + β1x1 + β2x12 + β3x2 + β4x22 + β5x1x2 + β6x1x22 + β7x12 x2 + β8x12 x22 + ɛ

b. Write the complete model for the sample data. Note that if there was replication at one or more design points, the number of degrees of freedom for SSLack would be identical to the difference between the number of parameters in the complete model and the number of parameters in the model of part (a).

In exercise

a. Can we test for lack of fit for the following model?

y = β0 + β1x1 + β2x12 + β3x2 + β4x22 + β5x1x2 + β6x1x22 + β7x12 x2 + β8x12 x22 + ɛ

b. Write the complete model for the sample data. Note that if there was replication at one or more design points, the number of degrees of freedom for SSLack would be identical to the difference between the number of parameters in the complete model and the number of parameters in the model of part (a).

In exercise

## Answer to relevant Questions

Refer to Example 13.1. a. Use a variable selection procedure to determine a model for this study. b. Do the model conditions appear to be valid for the model constructed in part (a)? Justify your answer. c. Use your fitted ...Refer to the data of Exercise 13.37. Test for lack of fit of a quadratic model. In exercise Dose Level Response 2………………………… 5, 7, 3 4…………………….. 10, 12, 14 8…………………….. 15, ...A random sample of 22 residential properties was used in a regression of price on nine different independent variables. The variables used in this study were as follows: PRICE = selling price (dollars) BATHS 5 number of ...A study was conducted to determine whether infection surveillance and control pro-grams have reduced the rates of hospital- acquired infection in U. S. hospitals. This data set consists of a random sample of 28 hospitals ...Refer to Exercise 13.72. Suppose you average the y- values for each of the unknowns and fit the ys in the linear regression model of Exercise 13.72. a. Do your linear regression lines change for each of the laboratories? b. ...Post your question