Statement $1$ : The variance of first $n$ odd natural numbers is $\frac{{{n^2} - 1}}{3}$
Statement $2$ : The sum of first $n$ odd natural number is $n^2$ and the sum of square of first $n$ odd natural numbers is $\frac{{n\left( {4{n^2} + 1} \right)}}{3}$
Statement $1$ is true, Statement $2$ is false.
Statement $1$ is true, Statement $2$ is true;
Statement $2$ is not a correct explanation for Statement $1$.
Statement $1$ is false, Statement $2$ is true.
Statement $1$ is true, Statement $2$ is true,
Statement $2$ is a correct explanation for Statement $1$.
The mean and the standard deviation (s.d.) of $10$ observations are $20$ and $2$ resepectively. Each of these $10$ observations is multiplied by $\mathrm{p}$ and then reduced by $\mathrm{q}$, where $\mathrm{p} \neq 0$ and $\mathrm{q} \neq 0 .$ If the new mean and new s.d. become half of their original values, then $q$ is equal to
Find the variance of the following data: $6,8,10,12,14,16,18,20,22,24$
Find the mean and variance for the data
${x_i}$ | $6$ | $10$ | $14$ | $18$ | $24$ | $28$ | $30$ |
${f_i}$ | $2$ | $4$ | $7$ | $12$ | $8$ | $4$ | $3$ |
Mean and standard deviation of 100 observations were found to be 40 and 10 , respectively. If at the time of calculation two observations were wrongly taken as 30 and 70 in place of 3 and 27 respectively, find the correct standard deviation.
If the mean and variance of the frequency distribution
$x_i$ | $2$ | $4$ | $6$ | $8$ | $10$ | $12$ | $14$ | $16$ |
$f_i$ | $4$ | $4$ | $\alpha$ | $15$ | $8$ | $\beta$ | $4$ | $5$ |
are $9$ and $15.08$ respectively, then the value of $\alpha^2+\beta^2-\alpha \beta$ is $............$.