A runner ran a time for the 100 meter sprint of 15.0 seconds at a school where the mean time for the 100 meter sprints is 17.5 seconds and the standard deviation is 2.1 seconds. A) find the z score of...

A runner ran a time for the 100 meter sprint of 15.0 seconds at a school where the mean time for the 100 meter sprints is 17.5 seconds and the standard deviation is 2.1 seconds.
A) find the z score of the runners time

b) use the z score to determine whether the value is unusual. Consider a score to be unusual if it's z score is less than -2.00 or greater than 2.00