If both the means and the standard deviation | vedclass

Name: PDF Generator App | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

Mean $\left( \mu  \right) = \frac{{\sum {{x_i}} }}{{50}} = 16$

Standard deviation $\left( \sigma  \right) = \sqrt {\frac{{\sum

Vedclass · Accepted Answer

$400$

Vedclass · Answer

Mean $\left( \mu  ight) = \frac{{\sum {{x_i}} }}{{50}} = 16$

Standard deviation $\left( \sigma  ight) = \sqrt {\frac{{\sum {x_i^2} }}{{50}} - {{\left( \mu  ight)}^2}}  = 16$

$ \Rightarrow \left( {256} ight) 	imes 2 = \frac{{\sum {x_i^2} }}{{50}}$

$\Rightarrow$ New mean

$ = \frac{{\sum {{{\left( {{x_i} - 4} ight)}^2}} }}{{50}} = \frac{{\sum {x_i^2 + 16 	imes 50 - 8\sum {{x_i}} } }}{{50}}$

$ = \left( {256} ight) 	imes 2 + 16 - 8 	imes 16 = 400$

Class	$10-20$	$20-30$	$30-40$
Frequency	$2$	$x$	$2$

Marks	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$	$70-80$
Group $A$	$9$	$17$	$32$	$33$	$40$	$10$	$9$
Group $B$	$10$	$20$	$30$	$25$	$43$	$15$	$7$

If both the means and the standard deviation of $50$ observations $x_1, x_2, ………, x_{50}$ are equal to $16$ , then the mean of $(x_1 - 4)^2, (x_2 - 4)^2, …., (x_{50} - 4)^2$ is

Similar Questions

If the variance of the following frequency distribution is $50$ then $x$ is equal to:

Class $10-20$ $20-30$ $30-40$

Frequency $2$ $x$ $2$

Let the six numbers $a_1, a_2, a_3, a_4, a_5, a_6$ be in $A.P.$ and $a_1+a_3=10$. If the mean of these six numbers is $\frac{19}{2}$ and their variance is $\sigma^2$, then $8 \sigma^2$ is equal to

The mean and $S.D.$ of the marks of $200$ candidates were found to be $40$ and $15$ respectively. Later, it was discovered that a score of $40$ was wrongly read as $50$. The correct mean and $S.D.$ respectively are...

The variance of the first $n$ natural numbers is

From the data given below state which group is more variable, $A$ or $B$ ?

Marks $10-20$ $20-30$ $30-40$ $40-50$ $50-60$ $60-70$ $70-80$

Group $A$ $9$ $17$ $32$ $33$ $40$ $10$ $9$

Group $B$ $10$ $20$ $30$ $25$ $43$ $15$ $7$