Question

Find the mean (μ), variance (σ²) and standard deviation (σ) for each of the following probability distributions:

(i)

 

(ii)

 

(iii)

 

(iv)

 

Answer 1

(i) Given :

To find : mean (μ), variance (σ²) and standard deviation (σ)

Formula used :

 

 

Mean = 1.2

Variance = 0.56

Standard deviation = 0.74

(ii) Given :

To find : mean (), variance (σ²) and standard deviation (σ)

Formula used :

Mean = 2

Variance = 1

Standard deviation = 1

(iii) Given :

To find : mean (), variance (σ²) and standard deviation (σ)

Formula used :

Mean = -0.8

Variance = 1.96

Standard deviation = 1.4

(iv) Given :

To find : mean (), variance (σ²) and standard deviation (σ)

Formula used :

Mean = 0

Variance = 1.2

Standard deviation = 1.095