University students were surveyed randomly on their opinion regarding a tuition increase. The minimum age recorded was 18 & the maximum age was 45. Use the range rule of thumb to estimate the standard deviation of the ages.

A: 27.0

B: 6.8

C: 7.9

D: 31.5

Answer is B.

Standard deviation is a measure of spread in statistics which tells about how the data is clustered around or close to the mean. There is a quick rule known as the Range Rule of Thumb by which we can estimate the standard deviation. According to the range rule of thumb, the range is approximately four times the standard deviation.

s ≈ R4

To use this rule, we may first find the range by subtracting the smallest value from the greatest value: 45 - 18 = 27

now divide the range by 4 to estimate the standard deviation:

s = 27/4 = 6.75 ≈ 6.8