Refer to the aphid data in Exercise 13.8. Obtain the residuals from the model you ­selected in Exercise 13.9.
a. Is there evidence in the residuals of a violation of the normality condition?
b. Is there evidence in the residual plots of a violation of the constant variance ­condition?
c. Perform a BP test for constant variance. Does the test agree with your observations in part (a)?
d. Determine the appropriate Box€“ Cox transformation for these data.
In exercise

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