# Question

Hormone replacement therapy (HRT) is thought to increase the risk of breast cancer. The accompanying data on x = percent of women using HRT and y = breast cancer incidence (cases per 100,000 women) for a region in Germany for = years appeared in the paper “Decline in Breast Cancer Incidence after Decrease in Utilisation of Hormone Replacement Therapy” (Epidemiology [2008]: 427–430). The authors of the paper used a simple linear regression model to describe the relationship between HRT use and breast cancer incidence.

a. What is the equation of the estimated regression line? y^ = 45.572 1 1.335x

b. What is the estimated average change in breast cancer incidence associated with a 1 percentage point increase in HRT use?

c. What would you predict the breast cancer incidence to be in a year when HRT use was 40%?

d. Should you use this regression model to predict breast cancer incidence for a year when HRT use was 20%? Explain.

e. Calculate and interpret the value of r2.

f. Calculate and interpret the value of se.

a. What is the equation of the estimated regression line? y^ = 45.572 1 1.335x

b. What is the estimated average change in breast cancer incidence associated with a 1 percentage point increase in HRT use?

c. What would you predict the breast cancer incidence to be in a year when HRT use was 40%?

d. Should you use this regression model to predict breast cancer incidence for a year when HRT use was 20%? Explain.

e. Calculate and interpret the value of r2.

f. Calculate and interpret the value of se.

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