Suppose that a random variable y has density function f(y) = ky3e−y/2 if y ≥0 and 0 otherwise. Find k which makes f(y) a density function. Then, find e(y ) and var y.

Answerthe simplified expression isexplanationthe given expression is,let us deal with the bracket first.the two negatives in the parenthesis will become positive.the expression now becomes,we now expand the parenthesis to get,we group like terms to obtain,this simplifies to,