Jim has started a new exercise program. He has monthly checkups where his percentage of body fat is measured. Jim records his body fat percentage and the number of months he has been on the exercise program. He collects data for 10 months and finds a linear model to give the relationship between the time spent exercising and his percentage of body fat. The equation of the line is ŷ = 17 – 1.25x, where ŷ is his percentage of body fat and x is the time spent exercising (in months). The residual plot is shown. Based on the residual plot, is the linear model appropriate?

No, there is no clear pattern in the residual plot.
Yes, there is no clear pattern in the residual plot.
No, there is a clear pattern in the residual plot, indicating that the linear model is not appropriate.
Yes, his percentage of body fat clearly decreases for the first four months and then increases after that.