What is the standard deviation of the following series

class $0-10$ $10-20$ $20-30$ $30-40$
Freq $1$ $3$ $4$ $2$

 

  • A

    $81$

  • B

    $7.6$

  • C

    $9$

  • D

    $2.26$

Similar Questions

The mean and variance of the marks obtained by the students in a test are $10$ and $4$ respectively. Later, the marks of one of the students is increased from $8$ to $12$ . If the new mean of the marks is $10.2.$ then their new variance is equal to :

  • [JEE MAIN 2023]

Find the standard deviation for the following data:

${x_i}$ $3$ $8$ $13$ $18$ $25$
${f_i}$ $7$ $10$ $15$ $10$ $6$

The sum of squares of deviations for $10$ observations taken from mean $50$ is $250$. The co-efficient of variation is.....$\%$

The frequency distribution:

$\begin{array}{|l|l|l|l|l|l|l|} \hline X & 2 & 3 & 4 & 5 & 6 & 7 \\ f & 4 & 9 & 16 & 14 & 11 & 6 \\ \hline \end{array}$

Find the standard deviation.

The $S.D.$ of a variate $x$ is $\sigma$. The $S.D.$ of the variate $\frac{{ax + b}}{c}$ where $a, b, c$ are constant, is