The following table shows the probability distribution for a discrete random

variable.

Х

11

14

16

19

21

23

24

29

P (X) 0.07 0.21

0.17 0.25 0.05 0.04 0.13 0.08

What is the mean of this discrete random variable? (That is, what is E (X), the

expected value of X?)

A. 19

B. 19.625

C. 20

D. 18.59

Because the random variable X is discrete, the variance of X is defined as

var (X) =

where

p = values of probability as given in the table.

μ = 18.59

Calculate the array (x - μ).

x-μ = [-7.59 - 4.59 - 2.59 0.41 2.41 4.41 5.41 10.41]

Calculate the array (x-μ) ².

(x - μ) ² = [57.6081 21.0681 6.7081 0.1681 5.8081 19.4481 29.2681 108.3681]

Calculate the array p * (x-μ) ².

p * (x - μ) ² = [4.0326 4.4342 1.1404 0.042 0.2904 0.7779 3.8049 8.6694]

Calculate the variance of X.

var (X) = 23.182

Step-by-step explanation:

Answer: 23.18 (nearest hundredth)