If the standard deviation of the numbers $2, 3, a$,and $11$ is $3.5$,then which of the following is true?

The variance of the numbers $8, 21, 34, 47, \ldots, 320$ is . . . . . . .

If the variance of the data $2, 4, 5, 6, 8, 17$ is $23.33$,then the variance of $4, 8, 10, 12, 16, 34$ will be

Two plants $A$ and $B$ of a factory show the following results regarding the number of workers and the wages paid to them:

\text{Parameter}	\text{Plant } $A$ \text{ and } $B$ \text{ Data}
\text{No. of workers}	$A: 500, B: 6000$
\text{Average monthly wages}	$A: Rs. 2500, B: Rs. 2500$
\text{Variance of distribution of wages}	$A: 81, B: 100$

In which plant,$A$ or $B$,is there greater variability in individual wages?

The mean and standard deviation of $100$ items are $50$ and $4$ respectively. The sum of the squares of all the items is:

Find the mean and variance for the first $10$ multiples of $3$.