If the mean of the data 7, 8, 9, 7, 8, 7 λ is 8,then the variance of this data is

Let the mean of the given observations is $\tilde{x} .$

$∴ \bar{x} = \frac{7 + 8 + 9 + 7 + 8 + 7 + λ + 8}{8} = 8 [∴ \bar{x} = 8$ (given)]

$\Rightarrow 54 + λ = 64 \Rightarrow λ = 64 - 54 = 10$

Now $Σ x_{i}^{2} = (7)^{2} + (8)^{2} + (9)^{2} + (7)^{2} + (8)^{2} + (7)^{2} + (10)^{2} + (8)^{2}$

$= 49 + 64 + 81 + 49 + 64 + 49 + 100 + 64 = 520$

Variance, $σ^{2} = \frac{\sum x_{i}^{2}}{n} - (\bar{x})^{2} = \frac{520}{8} - (8)^{2} = 65 - 64 = 1$

If the mean of the data 7, 8, 9, 7, 8, 7 $λ$ is 8,
then the variance of this data is