Answer to Question #305517 in Statistics and Probability for Vivek

Question

Let X be the number of life years before certain kind of CFL bulb needs replacement. Let

X have the probability mass function (pmf) is defined as

f(x) = ax° r = 0,1,2,3,4

where a is some real constant.

(a) Find the value of constant a.

(b) Find the commulative distribution function (cdf) F of X.