Question

Find the mean, variance, and standard deviation of the following probability

distribution then interpret the computed values. Write your answer in your answer
sheets.
The number of computers sold per day at a local computer store, along with its
corresponding probabilities, is shown in the table below.
Number of Computer Sold X
Probability P(x)
0
0.1
2
0.2
5
0.3
7
0.2
9
0.2​

Answer 1

5.1 ; 8.29 ; 2.879

Explanation:

Given :

Number of Computer Sold X

Probability P(x)

0

0.1

2

0.2

5

0.3

7

0.2

9

0.2

Mean = E(X) = Σ(x*p(x)

E(X) = (0*0.1) + (2*0.2) + (5*0.3) + (7*0.2) + (9*0.2)

E(X) = 5.1

Variance, Var(X) = Σx²p(x) − E(X)²

Var(X) = [(0^2*0.1) + (2^2*0.2) + (5^2*0.3) + (7^2*0.2) + (9^2*0.2)] - 5.1^2

Var(X) = 34.3 - 26.01 = 8.29

Standard deviation ; Std(X) = √Var(X) = √8.29 = 2.879