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=-1.004
b = 32.878
r^2=0.426409
r=-0.653
use this to predict the number of situps a person who watches 9 hours of tv can do (to one decimal place)

Explanation:

Step1: Identify the regression equation

The regression equation is $\hat{y}=ax + b$, where $a=-1.004$ and $b = 32.878$.

Step2: Substitute the value of x

We want to predict the number of situps when $x = 9$. Substitute $x = 9$ into the equation $\hat{y}=-1.004\times9+32.878$.

Step3: Calculate the result

First, calculate $-1.004\times9=-9.036$. Then, $\hat{y}=-9.036 + 32.878=23.842$. Rounding to one - decimal place, we get $\hat{y}\approx23.8$.

Answer:

$23.8$