What is the standard deviation of the following series
class |
0-10 |
10-20 |
20-30 |
30-40 |
Freq |
1 |
3 |
4 |
2 |
$81$
$7.6$
$9$
$2.26$
The variance of the data $2, 4, 6, 8, 10$ is
The variance of the first $n$ natural numbers is
If $\sum\limits_{i = 1}^{18} {({x_i} - 8) = 9} $ and $\sum\limits_{i = 1}^{18} {({x_i} - 8)^2 = 45} $ then the standard deviation of $x_1, x_2, ...... x_{18}$ is :-
If the variance of the frequency distribution is $3$ then $\alpha$ is ......
$X_i$ | $2$ | $3$ | $4$ | $5$ | $6$ | $7$ | $8$ |
Frequency $f_i$ | $3$ | $6$ | $16$ | $\alpha$ | $9$ | $5$ | $6$ |
If the mean deviation about median for the number $3,5,7,2\,k , 12,16,21,24$ arranged in the ascending order, is $6$ then the median is