Mean of $5$ observations is $7.$ If four of these observations are $6, 7, 8, 10$ and one is missing then the variance of all the five observations is

  • [JEE MAIN 2013]
  • A

    $4$

  • B

    $6$

  • C

    $8$

  • D

    $2$

Similar Questions

If the mean and variance of five observations are $\frac{24}{5}$ and $\frac{194}{25}$ respectively and the mean of first four observations is $\frac{7}{2}$, then the variance of the first four observations in equal to

  • [JEE MAIN 2024]

For a frequency distribution, standard deviation is computed by

If the variance of the frequency distribution is $3$ then $\alpha$ is ......

$X_i$ $2$ $3$ $4$ $5$ $6$ $7$ $8$
Frequency $f_i$ $3$ $6$ $16$ $\alpha$ $9$ $5$ $6$

 

  • [JEE MAIN 2023]

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

  • [JEE MAIN 2018]

Find the standard deviation for the following data:

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