Question

he mean of a set of 10 numbers is 65. If a number is removed from the set, the mean changes to 63.
The number removed is ________.

Answer 1

The removed number is 83. Sum of observations of the set with 10 numbers= 65 ×10=650. Sum of observations of the set with 9 numbers=63×9 =567. The removed number=sum of observations of the set with 10 numbers - sum of observations of the set with 9 numbers= 650-567 =83. Hope this helps you :))

Answer 2

Mean of 10 numbers = 65
Sum of the numbers = 65×10 = 650

when one number is removed,
number of numbers = 9
their mean = 63
sum = 63×9 = 567

The removed number = 650 - 567 = 83