# Question

Refer to Exercise 11.70.
a. The researcher consulted with a statistician, and a transformation of the data was suggested. Plot the square root of CUMVOL versus the logarithm of dose in a scatterplot. Do the plotted points appear to be more closely related by a straight line than were the raw data values?
b. Fit a regression model relating the square root of CUMVOL to the logarithm of dose.
c. Test for lack of fit of this model at the a = .05 level.
d. Estimate the mean value of CUMVOL for a dose level of 15 using a 95% confidence interval based on the model obtained in part (b).
e. How large are the differences in the two estimates of the mean CUMVOL?
In exercise

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