Suppose Fx 183x2 8x 412 2 x 6 is the cdf for the random
Suppose F(x) = (1/8)(3x^2 - 8x + 4)^(1/2), 2 ? x ? 6, is the c.d.f. for the random variable X. Find (a) P (X ? 5), (b), P(3 < X < 4), and (c) the p.d.f. of X.
Please explain the steps to get the answer to these problems. Thanks!
Solution
F(x) = (1/8)(3x^2 - 8x + 4)^(1/2), 2 <= x <= 6,
F(6) = 1/8 (108-48+4)^(1/2) = 1
F(x) is a cdf
a) P(X<5) = F(5) = rt39/8
b) P(3 < X < 4) = F(4)-F(3) = 1/8(21-8+4) 1/2= rt17/8
c) f(x) = pdf of x= derivative of F
= (3x-4)/4, 2<=x<=6
