Answer
$X_{0.95}^2=17.708$
$X_{0.05}^2=42.557$
Work Step by Step
$n=30$. So:
$d.f.=n-1=29$
$level~of~confidence=(1-α).100$%
$90$% $=(1-α).100$%
$0.9=1-α$
$α=0.1$
$X_{1-\frac{α}{2}}^2=X_{0.95}^2=17.708$
(According to Table VII, for d.f. = 29 and area to the right of the critical value = 0.95)
$X_{\frac{α}{2}}^2=X_{0.05}^2=42.557$
(According to Table VII, for d.f. = 29 and area to the right of the critical value = 0.05)
