Question

What should be the value of x so that mean of the data is 16?
7,13,15,15,16,x,19,20

Answer 1

Mean = sum of all observations / Number of observations

=> 16 = ( 7 + 13 + 15 + 15 + 16 + x + 19 + 20) / 8

=> 16 × 8 = 20 + 30 + 35 + 20 + x

=> 128 = 105 + x

=> x = 128 - 105

=> x = 23

Answer 2

STEP 1: Find the average:

Sum of all the 8 numbers = 7 + 13 + 15 + 15 + 16 + x + 19 + 20

Sum of all the 8 numbers = 105 + x

.

Average = (105 + x) ÷ 8

Average = (105 + x)/8

.

STEP 2: Find x:

Average = (105 + x)/8

Average = 16

.

(105 + x)/8 = 16

105 + x = 128

x = 23

.

Answer: x =23