Question

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with astandard deviation of 0.3 minute. What is the probability that a runner will run the mile in less than 4 minutes?

Possible Answers:
A)7%B)3%C)5%D)4%

I know it's C, but I don't know how to get it.

Answer 1

z-score
z=(x-mu)/sigma
then look it up : ) on your tables
z=1.666
your table is a less than table so the value will be the correct percent.