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:

23.18 (nearest hundredth)

the line of