Question

The times for running a 5K for a local charity event are Normally distributed with a mean time of 28 minutes and

standard deviation of 5.4 minutes. Which time represents the 60th percentile?
Find the z-table here.

A. 19.6 minutes
B. 26.6 minutes
C. 29.4 minutes
D. 36.4 minutes

Answer 1

29.4 minutes represents the 60th percentile

Explanation:

Given : The times for running a 5K for a local charity event are Normally distributed, with a mean time of 28 minutes and standard deviation of 5.4 minutes.

To Find : Which time represents the 60th percentile?

19.6 minutes

26.6 minutes

29.4 minutes

36.4 minutes

Solution:

time represents the 60th percentile

Means 60 % data = 0.6 below this

from z table , z score for this = 0.253

z score = ( Value - Mean ) / SD

=> 0.253 = ( Value - 28 ) /5.4

=> 1.3662 = Value - 28

=> Value = 29.3662

=> Value = 29.4

29.4 minutes represents the 60th percentile