Question

The S.D. and C.V. for the following frequency distribution is

xi	60	61	62	63	64	65	66
fi	3	10	11	13	7	5	1

Options

• 2.12 and 2.33

• 3.12 and 3.33

• 1.46 and 2.33

• 1.46 and 3.33

Answer 1

1.46 and 2.33

Explanation:

Here, ∑f_i = 50, ∑f_ix_i = 3130,

`sumf_i(x_i - overlinex)^2 = 106`

∴ `overlinex = (sumf_ix_i)/(sumf_i) = 3130/50 = 62.6`

∴ `sigma = sqrt(1/Nsumf_i(x_i - overlinex)^2) = sqrt(106/50) = 1.46`

∴ C.V. = `sigma/|overlinex| xx 100 = 2.33`