A regression was run to determine if there is a relationship between hours of TV watched per day (x) and number of situps a person can do (y).

The results of the regression were:
y=ax+b
a=-1.154
b=39.771
r2=0.386884
r=-0.622

Use this to predict the number of situps a person who watches 8 hours of TV can do (to one decimal place)