Answer
$t_0\gt t_{\frac{α}{2}}$: null hypothesis is rejected.
There is enough evidence to conclude that a linear relation exists between 7-day strength and 28-day strength.
Work Step by Step
$H_0: β_1=0$ versus $H_1: β\ne0$
$t_0=\frac{b_1}{s_{b_1}}=\frac{0.676}{0.2055}=3.290$
$n=10$, so:
$d.f.=n-2=8$
$t_{\frac{α}{2}}=t_{0.025}=2.306$
(According to Table VI, for d.f. = 8 and area in right tail = 0.025)
Since $t_0\gt t_{\frac{α}{2}}$, we reject the null hypothesis.
