Question

The mean of 20 observations is 45.by an error one observation is registered as 52 instead of 25 .find the correct mean

Answer 1

hey!

mean is founded by total sum of observations divided by the no of times the no of observation has occurred

correct mean = total no -wrong no + correct no / total no of registered no

= 45*20-52+25/20

=925-52/20

=873/20

=43.65

Answer 2

Que:- The mean of 20 observations is 45.by an error one observation is registered as 52 instead of 25 .find the correct mean.

Solution:-

Mean ( Average) = Sum of Observation/ Number of Observation

=> 45 = Sum of 20 Observation/ 20

=> Sum of 20 Observation = 20 × 45

=> Sum of 20 Observation = 900.

Now, By mistake one Observation is registered wrong.

So, Removing Wrong Observation = 900 - 52

=> 848.

Now, Adding the correct Observation = 848 + 25

=> Sum of Observation = 873.

Now, Mean = 873 / 20

=> Mean = 43.65