If mean of following data is 21.5, then find K :
Class 0-10 10-20 20-30 30-40 40-50
Frequency 6 4 3 K 2

Open in App

Solution

$∵ A r i t h m e t i c m e a n = \frac{\sum f_{i} x_{i}}{\sum f_{i}}$
$21.5 = \frac{255 + 35 K}{15 + K}$
$\Rightarrow 322.5 - 255 = 35 K - 21.5 k$
$\Rightarrow 13.5 k = 67.5$
$K = \frac{67.5}{13.5} = 5$
$∴ K = 5$

Suggest Corrections

Similar questions

Q. Calculate mean deviation about for the following data.

Class	0-10	10-20	20-30	30-40	40-50	50-60
Frequence	6	7	15	16	4	2

Q. Calculate mean deviation about Median for the following data :

Class	0-10	10-20	20-30	30-40	40-50	50-60
Frequency	6	7	15	16	4	2

Q. Find mean of the following frequency distribution taking assumed mean 25.

Class	0-10	10-20	20-30	30-40	40-50
$f$	6	10	13	7	4

Find the mean of the following data, using direct method:
$\begin{matrix} Class & 0 - 10 & 10 - 20 & 20 - 30 & 30 - 40 & 40 - 50 & 50 - 60 Frequency & 7 & 5 & 6 & 12 & 8 & 2 \end{matrix}$

If the mean of the following frequency distibution is 24, find the value of p.
$\begin{matrix} Class & 0 - 10 & 10 - 20 & 20 - 30 & 30 - 40 & 40 - 50 Frequency & 3 & 4 & p & 3 & 2 \end{matrix}$

Join BYJU'S Learning Program

If mean of following data is 21.5, then find K :Class0-1010-2020-3030-4040-50Frequency643K2

∵Arithmeticmean=∑fixi∑fi21.5=255+35K15+K⇒322.5−255=35K−21.5k⇒13.5k=67.5K=67.513.5=5∴K=5

If mean of following data is 21.5, then find K :
Class 0-10 10-20 20-30 30-40 40-50
Frequency 6 4 3 K 2

$∵ A r i t h m e t i c m e a n = \frac{\sum f_{i} x_{i}}{\sum f_{i}}$
$21.5 = \frac{255 + 35 K}{15 + K}$
$\Rightarrow 322.5 - 255 = 35 K - 21.5 k$
$\Rightarrow 13.5 k = 67.5$
$K = \frac{67.5}{13.5} = 5$
$∴ K = 5$