Question

The variance of the data 3, 6, 9, 12, 15 is ______

Options

• 6

• 7

• 18

• None of these

Answer 1

The variance of the data 3, 6, 9, 12, 15 is 18.

Explanation;

Here, `overlinex = (3 + 6 + 9 + 12 + 15)/5 = 9`

∴ variance = `1/nsum(x_i - overlinex)^2`

= `1/5{(3 - 9)^2 + (6 - 9)^2 + (9 - 9)^2 + (12 - 9)^2 + (15 - 9)^2}`

= `1/5{36 + 9 + 0 + 9 + 36}`

= `1/5{90}`

= 18