SOLUTION: Let X be a continuous random variable with density function f(x) = { theta*x + 3/2*theta^{3/2}*x^2, for 0 < x < 1/sqrt( theta ); 0, otherwise } where theta > 0. What is the expec

Algebra ->  Probability-and-statistics -> SOLUTION: Let X be a continuous random variable with density function f(x) = { theta*x + 3/2*theta^{3/2}*x^2, for 0 < x < 1/sqrt( theta ); 0, otherwise } where theta > 0. What is the expec      Log On


   



Question 1203892: Let X be a continuous random variable with density function
f(x) = { theta*x + 3/2*theta^{3/2}*x^2, for 0 < x < 1/sqrt( theta ); 0, otherwise }
where theta > 0. What is the expected value of X?

Answer by math_tutor2020(3816) About Me  (Show Source):
You can put this solution on YOUR website!

To find the expected value, we apply the integral to x*f(x) over the limits from -infinity to infinity.

E(x) = expected value


Because much of the real number line makes f(x) = 0, we only need to worry about the interval 0+%3C+x+%3C+1%2F%28sqrt%28theta%29%29 which is the same as 0+%3C+x+%3C+sqrt%281%2Ftheta%29 where theta > 0

The goal has been reduced to computing


Using fairly elementary calculus integration rules, you should find that:




For some constant C.

Then,



and








Subtract the two results to find





Therefore, the expected value is where theta > 0