Question

the mean of the 12 observation is 20 . what is their sum?​

Answer 1

Step-by-step explanation:

Arithmetic mean of 12 observations is 15.

Thus, sum of 12 observations = 180

After removing 25 and 20 from the series, sum of 10 observations = 180−25−20=135

Thus, mean =

number

sum

=

10

135

=13.5

Answer 2

Answer:

Sum of observations  is $240$ .

Step-by-step explanation:

To find : sum of observations .

Given :  mean of the $12$  observation is $20$.

Solution :

• Average is the arithmetic mean also called as mean .  
• It is the ratio of sum of all the numbers given in data to the total number of observations.
• Formula: $Average \ or \ mean =\frac{\text { sum of all the observations }}{\text { total of observations }}$
• Let , sum of observations be $x$
• Total number of observations $= 12$
• Mean = $20$
• Substituting values in above formula,

        $20 = \frac{x}{12} \\\\ x = 20\times 12\\\\ x =240$