Question

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=-1.072
b=22.446
r2=0.383161
r=-0.619
Assume the correlation is significant, and use this to predict the number of situps a person who watches 2.5 hours of TV can do (to one decimal place)

Answer 1

19.8 sit ups

Explanation:

Given

The results of regression

`a=-1.072`

`b=22.446`

`r^2=0.383161`

`r=-0.619`

Required

Predict y when x = 2.5

First, we determine the regression equation using:

`y =ax + b`

So, we have:

`y = 1.072x + 22.446`

Substitute 2.5 for x to get the number of situps (y)

`y = -1.072*2.5 + 22.446`

`y = -2.68 + 22.446`

`y = 19.766`

Approximate

`y = 19.8`