Question

The mean of 15 number is 18, if one number is excluded , their mean is 16 . Find the excluded mean.

Answer 1

n=15,x bar =18. Incorrect sigma x=x bar *n=18*15=270,correct sigmax=incorrect sigma x-wrong+correct=270-18+16=268.correct x bar=correct sigmax/n=268/15=17.866.....

Answer 2

The mean of 15 numbers is 18

therefore there sum is 15×18=270

After excluding one number there mean is 16

So there sum is 16×14=224

So excluded number= 270-224

=46