Answer
$F_0\lt F_{1-α,n_1-1,n_2-1}$: null hypothesis is rejected.
There is enough evidence to conclude that $σ_1\ltσ_2$
Work Step by Step
$F_0=\frac{s_1^2}{s_2^2}=\frac{15.9^2}{23.0^2}=0.48$
$d.f_1=n_1-1=21-1=20$
$d.f_2=n_2-1=26-1=25$
Left-tailed test:
$F_{α,n_1-1,n_2-1}=F_{0.05,20,25}=2.01$
(According to table VIII, for $d.f._1=20$, $d.f._2=25$ and area in the right tail = 0.05)
$F_{1-α,n_1-1,n_2-1}=F_{0.95,20,25}=\frac{1}{F_{0.05,20,25}}=\frac{1}{2.01}=0.50$
Since $F_0\lt F_{1-α,n_1-1,n_2-1}$, we reject the null hypothesis.
