Question

the mean of 20 observation is 54 if one observation 42 is misread as 24 find the Newmean

Answer 1

mean=su.of observations/no of observations
here no of obs are 20 and mean is 54 so sumof observations=54×20=1080
42 is misread as 24
so correct mean =sum of obs-wrongobs+correctobs/no of obs
so 1080-24+42/20=54.9

Answer 2

Answer:

Mean = No of observation

number of observation are 20 and mean is 54

So, sum of observation is 54 x 20 = 1080

So, correct mean = number of observation

So, 1080-24+42÷20.

= 1056+42÷20.

=1098÷20.

=54.9