Question

Coefficients of variation of two distributions are 30 and 40 and their arithmetic means are 10 and 25 respectively. The difference of their standard deviations is ______ 

Options

• 7

• 1

• 0

• 2.5

Answer 1

Coefficients of variation of two distributions are 30 and 40 and their arithmetic means are 10 and 25 respectively. The difference of their standard deviations is 7. 

Explanation:

Let the standard deviations of two distributions be σ₁ and σ₂ respectively. Then,

`30 = sigma_1/10 xx 100` and `40 = sigma_2/25 xx 100`

∴ σ₁ = 3 and σ₂ = 10

⇒ σ₂ - σ₁ = 7