If the variance of $6, 7, 8, 9, 10, 11$ is $\sigma^2$,then the variance of $12, 14, 16, 18, 20, 22$ is

The standard deviation of the numbers $31, 32, 33, \ldots, 46, 47$ is

$5$ students of a class have an average height $150 \, cm$ and variance $18 \, cm^2$. $A$ new student,whose height is $156 \, cm$,joined them. The variance (in $cm^2$) of the height of these $6$ students is

If $\sum_{i = 1}^9 (x_i - 5) = 9$ and $\sum_{i = 1}^9 (x_i - 5)^2 = 45$,then the standard deviation of the $9$ items $x_1, x_2, ..., x_9$ is:

If the standard deviation of the first $n$ natural numbers is $2$,then the value of $n$ is

The variance of $^{10}C_0, ^{10}C_1, ^{10}C_2, \dots, ^{10}C_{10}$ is: