**20. Correct. The
answer is true**

(a) v_{1
}=15, v_{2}=9, and F_{0.99, 15, 9 }= 4.96

(b) By
Theorem 4-8, p.118, F_{0.01, 15, 9 }= ( F_{0.99, 15, 9})^{-1
}= 0.257

(c) v_{1
}=10, v_{2}=15, and F_{0.95, 10, 9}=
2.54

(d) By
Theorem 4-8, p.118 in Schaum's Outline, F_{0.05,
8, 30 }= ( F_{0.05, 8, 30})^{-1 }= 0.325