Question

A computer programmer creates a probability distribution table when working with generated values appearing in a program. She determines that the mean of the probability distribution is 65.1 and the standard deviation is 9.7. If the value 84.9 appeared, would it be considered usual or unusual? Why?

A.
Usual, because the result is within the range of the minimum and maximum usual values.

B.
Unusual, because the result is within the range of the minimum and maximum usual values.

C.
Usual, because the result is greater than the maximum usual value.

D.
Unusual, because the result is greater than the maximum usual value.

Answer 1

D, unusual because the number is greater than the max usual value

Answer 2

D.

Unusual, because the result is greater than the maximum usual value.

Explanation:

Given that the computer programmer creates a probability distribution table.

Mean was found to be 65.1 and the std devi =9.7

By use of control chart, and conventions about any data we find that if any entry lies within 3 std deviations of the mean, that is usual.

Here let us calculate the range

Mean - 3 std dev = 65.1-3(9.7) = 65.1-29.1 =36

Mean+3 std dev =65.1+3(9.7) = 65.1+29.1 = 84.2

The item quoted is 84.9 which is higher than the range of (36,84.2)

Hence this can be treated as unusual.

D.

Unusual, because the result is greater than the maximum usual value.