Question

For a data consisting of 9 observations, the sum of 9 values is 360 and the sum of squares of deviation taken from the mean is 288. Find the mean and variance of the observation.

Answer 1

4 ; 32

Explanation:

Given that :

Number of observations, n = 9

Let observations = X

ΣX = 360

The mean, (m) is calculated using the formula :

m = ΣX / n

m = 360 / 9

m = 4

Σ(X - m) = 288 (sum of square of deviation )

Variance is calculated using the formula :

[Σ(X - m) / n]

Variance = Sqrt(288 / 9)

Variance = 32