An article in Wear presents data on the fretting wear of mild steel and oil viscosity. Representative data follow, with x = oil viscosity and y = wear ear volume (10 - 4 cubic millimeters). y 240 181...

An article in
Wear
presents data on the fretting wear of mild steel and oil viscosity. Representative data follow, with
x
= oil viscosity and
y
= wear ear volume (10<sup>-

4</sup>cubic millimeters).

presents data on wear volume
y
and oil viscosity
x.

(a) Calculate
R
²for this model. Provide an interpretation of this quantity.

(b) Plot the residuals from this model versus
and versus
x. Interpret these plots.

(c) Prepare a normal probability plot of the residuals. Does the normality assumption appear to be satisfied?