Answer
$t_0\lt -t_α$, we reject the null hypothesis.
There is enough evidence to conclude that the repair cost for the car is higher than the repair cost for the SUV.
Work Step by Step
$d_i=(SUV~Damage)_i-(Car~Damage)_i$
$d_1=447$
$d_2=-893$
$d_3=-2373$
$d_4=271$
$d_5=-1680$
$d_6=-1916$
$d_7=-1676$
$d ̅=\frac{∑d_i}{n}=-1117.14$
$s_d=\sqrt {\frac{∑(d_i-d ̅)^2}{n-1}}=1100.62$
$H_0:~µ_d=0$ versus $H_1:~µ_d\lt0$
$t_0=\frac{d ̅ }{\frac{s_d}{\sqrt n}}=\frac{-1117.14}{\frac{1100.62}{\sqrt 7}}=-2.685$
$n=7$, so:
$d.f.=n-1=6$
Left-tailed test:
$t_α=t_{0.05}=1.943$
(According to Table VI, for d.f. = 6 and area in right tail = 0.05)
So, $-t_α=-1.943$
Since $t_0\lt -t_α$, we reject the null hypothesis.
