Question

Given that one standard deviation below the mean is 24 and one standard deviation above the mean is 31, what is the mean l?

A)55
B)34
C)27.5
D)28

Answer 1

C. 27.5

Explanation:

since 24 and 31 are one standard deviation below or above the mean, we could subtract the two values and divide them by two to help find the mean.

we would first subtract the two values

• 31-24 = 7

we would then divide that number by 2 since we are finding the average between the two numbers

• 7/2 = 3.5

using the 3.5, you add it to the lower value (24) and subtract it from the higher value (31)

• 24+3.5 = 27.5
• 31-3.5 = 27.5

since both calculated numbers were equal, we know that we calculated the mean correctly.