Question

Mean of eight observations is 25. If one observation 11 is excluded , find the mean of the remaining.​

Answer 1

Mean = 27

Explanation:

Given mean = 25

No of observations (N) = 8

We know,

Mean = Sum / N

25 = Sum / 8

Sum = 25 x 8

Sum = 200

Since an observation 11 is removed,

New sum = 200 - 11 = 189

New no. of observation (N) = 8 - 1 = 7

Now,

Mean of remaining observations = New Sum / New N

= 189/7

= 27

Answer 2

mean=25

n=8

sum of observation=?

we have

mean=sum/n

sum=25×8=200

if one observation is excluded

sum will be =200-11=189

[n]no of observation = 8-1=7

new mean =new sum/new n=189/7=27

the mean of the remaining is 27