Given:
\(\displaystyle{n}=\ \text{Sample size}\ ={60}\)
a) PSB is on the horizontal axis and Thickness is on the vertical axis.
b) It is reasonable to find a regression line for the data if there is no strong curvature present in the scatterplot.
We note that there is strong curvature in the scatterplot of part (a) and thus it is not reasonable to find a regression line for the data.
c) Nor applicable, because it is not reasonable to find a regression line by part (b).
d) Nor applicable, because it is not reasonable to find a regression line by part (b).
e) Nor applicable, because it is not reasonable to find a regression line by part (b).
f) Nor applicable, because it is not reasonable to find a regression line by part (b).