# 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

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

## Answer to relevant Questions

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