A random variable has the following probability mass functio

A random variable has the following probability mass function

x 1 2 3 4

p(x) .2 .3 .3 .2

What is the expected value of X?

What is the cumulative distribution for X?

Solution

a)

Consider:

E(x) = SUm(xP(x)) = Expected value = mean =    2.5 [ANSWER]

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What is the cumulative distribution for X?

Hence,

F(x) = 0, x < 1
0.2, 1<=x<2
0.5, 2<=x<3
0.8, 3<=x<4
1, 4<=x