Question

The mean of 25 observations is 27. If one observation is included, the mean still remains
27. Find the included observation.​

Answer 1

Answer:

27

Step-by-step explanation:

Mean = Sum of observations / Number of observations

Let the the sum of 25 observations be "x" and the added observation be "y" then

In first case

27 = x/25

x = 675

In second case when "y" is added

27 = (x + y) / 26

x + y = 702

y = 702 - x

y = 702 - 675

y = 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