Question

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. Find the percentage of a runners that will run the mile in less than 4 minutes?
A. 45.22%

B. 15.87%

C. 7.15%

D. 4.75%

Answer 1

4 is .5 less than the mean of 4.5
To get the z score for this, just do .5 / .3
The z score will be negative, since you're considering something less than the mean. Look up a z score chart and figure out the percentage of the data that will be less than that z score.

Answer 2

thanx

Answer 3

You're welcome =D