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=-1.336

b=25.984

r²-0.375769

r=-0.613

Use this to predict the number of situps a person who watches 13 hours of TV can do (to one decimal place)