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=-0.842 b=20.276 r2=0.712336 r=-0.844 

Use this to predict the number of situps a person who watches 3.5 hours of TV can do (to one decimal place)