Question

the mean of 25 observations is 27.if one obeservation is included,the mean still remains 27.find the included observation​

Answer 1

Given

The mean of 25 observations is 27

So,

The total sum of all the 25 observations =27×25=675

After one observation is included

Now, the mean of 26(25+1)numbers=27

So,

The total sum of all the 26 observations =27×26=702

Hence,

The included observation =702−675=27

Answer 2

Given,

The mean of 25 observations is 27.

So,

The total sum of all the 25 observations = 27 x 25 = 675

After one observation is included,

Now the mean of 26 (25 + 1) numbers = 27

So,

The total sum of all the 26 observations = 27 x 26 = 702

Hence,

The included observation = 702 – 675 = 27