Question

The mean of 15 observations is 8. If the mean of the first eight observations is 7 and that of the last eight observations is 10, then the value of the 8th observation is 16.

• A. True
• B. False

Answer 1

The correct option is A

True

Sum of all the observations = 15 x 8 = 120.

Sum of first eight observations = 56

Sum of the last eight observations = 80.

Hence, the value of the $8^{th}$observation = (80 + 56) - 120 = 16