The mean square deviation of a set of n observations x1,x2,.......xn about a point c is defined as 1nn∑i=1(xi−c)2. The mean square deviation about –2 and 2 are 18 and 10 respectively, then standard deviation of this set of observations is

The mean square deviation of a set of n observations x1,x2,.......xn a

1.	The mean square deviation of a set of n observations x1,x2,.......xn about a point c is defined as 1nn∑i=1(xi−c)2. The mean square deviation about –2 and 2 are 18 and 10 respectively, then standard deviation of this set of observations is
Answer» The mean square deviation of a set of $n$ observations $x_{1}, x_{2}, . . . . . . . x_{n}$ about a point $c$ is defined as $\frac{1}{n} n \sum i = 1 (x_{i} - c)^{2}$ . The mean square deviation about $- 2$ and $2$ are $18$ and $10$ respectively, then standard deviation of this set of observations is