Question

The variance of a series of numbers is the sum of the squares of their differences from the mean (average) of the numbers divided by the number of items in the series. Variance is a common measure of risk. What is the variance of these investment returns? 10, 30, 20

Answer 1

Answer: 66.7

Step-by-step explanation:

Answer 2

Answer: 66.67

Step-by-step explanation:

Numbers given = 10, 30, 20

Mean = (10 + 30 + 20) / 3

= 60/3

= 20

Then, the differences from the mean will be:

= (10 - 20), (30 - 20), (20 - 20)

= -10, 10, 0

We then calculate the square of the mean which will be:

= 100, 100, 0

We then add the square of the mean which will be:

= 100 + 100 + 0

= 200

The variance will then be:

= 200/3

= 66.67