In the article“Nonablative facial remodeling: erythema reduction and histologic evidence of new collagen formation using a 300-microsecond 1064-nm Nd:YAG laser”

published in the Archives of Dermatology (Schmults et al., 2004), the data given in Table 8.7 were reported for a study of the change in collagen fiber diameter and patient’s age. Use the data in Table 8.7 to answer the following questions about the relationship between change in collagen fiber after 3 months of treatment and patients age.

(a) Draw a scatterplot of diameter change (????) versus patient’s age (????).

(b) Fit a simple linear regression model relating diameter change to patient’s age.

(c) Check the validity of the simple linear regression assumptions.

(d) Determine the equation of the least squares regression line.

(e) Determine the value of the coefficient of determination.

(f) Test ????0 ∶ ????1 = 0 at the ???? = 0.05 level.

(g) Create a fitted line plot for the observed data on diameter change and patient’s age.