If X is χ2(12), find constants a and b such that P(a < X < b) = 0.90 and P(X < a) = 0.05.

Question

 If X is χ2(12), find constants a and b such that
P(a < X < b) = 0.90 and P(X < a) = 0.05.

Answer 1

P(X<a)=0.05

so from chi-square table a=5.226

As P(a<x<b)=0.90

P(X<b)-P(X<a)=0.90

P(X<b)= 0.95

so from chi-square table b=21.03