Question

Let x₁, x₂ ,..., x_n be n observations such that `sumx_1^2` = 400 and `sumx_i` = 80. Then, a possible value of n among the following is:

Options

• 12

• 9

• 18

• 15

Answer 1

18

Explanation:

Given that, `sumx_1^2` = 400 and `sumx_i` = 80

∵ σ² ≥ 0

∴ `(sumx_1^2)/n - ((sumx_i)/n)^2 ≥ 0`

`\implies 400/n - 6400/n^2 ≥ 0`

∴ n ≥ 16