Question

The mean of 50 observations is 39. If one of the observations which was 23 was replaced by 43, theresulting mean will be​

Answer 1

Given

Mean of 50 observations = 39.

To Find

Mean observation when 23 which is one of the observation is replaced by 43.

Formula

$\boxed{Mean\:=\: \dfrac{Sum\:of\:all\:observation}{Number\:of\:observation}}$

Calculations

Sum of all observations = Mean × No. of obs.

=> S = 39 × 50

=> S = 1950

New sum = 1950 - 23 + 43

= 1970.

Number of all observations is still 50.

Hence,

$Mean\:=\: \dfrac{1970}{50}\\ \\ =>\: Mean\:= 39.4$

Hence,the new mean is 39.4

Answer 2

Step-by-step explanation:

mean = sum of all observations

no. of observation

so, (mean) (no. of observations) = sum of obser.

( 50)(39)= 1950

sum of observation. = 1950

now, mean when 23 is replaced to 43

mean= 1950+ 20

50

= 1970/50

mean = 39.4