The outcome of each of $30$ items was observed; $10$ items gave an outcome $\frac{1}{2} - d$ each,$10$ items gave an outcome $\frac{1}{2}$ each,and the remaining $10$ items gave an outcome $\frac{1}{2} + d$ each. If the variance of this outcome data is $\frac{4}{3}$,then $|d|$ equals:

Let $x_1, x_2, \dots, x_n$ be the values taken by a variable $X$ and $y_1, y_2, \dots, y_n$ be the values taken by a variable $Y$ such that $y_i = ax_i + b$,where $i = 1, 2, \dots, n$. Then...

Suppose a population $A$ has $100$ observations $101, 102, . . ., 200$ and another population $B$ has $100$ observations $151, 152, . . ., 250$. If $V_A$ and $V_B$ represent the variances of the two populations,respectively,then $V_A / V_B$ is:

The standard deviations of $x_i (i=1, 2, \ldots, 10)$ and $y_i (i=1, 2, \ldots, 10)$ are $a$ and $b$ respectively. $\bar{x}$ and $\bar{y}$ are the means of these two sets of observations. If $z_i = (x_i - \bar{x})(y_i - \bar{y})$ and $\sum_{i=1}^{10} z_i = c$,then the standard deviation of the observations $(x_i - y_i)$ for $i=1, 2, \ldots, 10$ is:

For the following frequency distribution,find the variance:

$X$	$5$	$6$	$7$	$8$	$10$
Frequency	$3$	$7$	$4$	$2$	$4$

If each of given $n$ observations is multiplied by a certain positive number $k$,then for the new set of observations -