The average time it takes college freshmen to complete the Mason Basic Reasoning Test is 38.3 minutes. The standard deviation is 3.2 minutes. Assume the variable is normally distributed.
Find the probability that it will take a student less than 30 minutes or more than 45 minutes to complete the test.

I REALLY NEED HELP :(

Question

The average time it takes college freshmen to complete the Mason Basic Reasoning Test is 38.3 minutes. The standard deviation is 3.2 minutes. Assume the variable is normally distributed.
Find the probability that it will take a student less than 30 minutes or more than 45 minutes to complete the test.

 I REALLY NEED HELP :(

kropot72 · Answer

First you need to find the z-scores for 30 minutes and 45 minutes using the formula:
$$z=\frac{X-\mu}{\sigma}$$
Can you do that?

kropot72 · Answer

The z-score for 30 minutes is
$$z _{1}=\frac{30-38.3}{3.2}=you\ can\ calculate$$

kropot72 · Answer

@mjm Are you there?