Question

The time required to finish a test in normally distributed with a mean of 40 minutes and a standard deviation of 8 minutes. What is the probability that a student chosen at random will finish the test in less than 48 minutes?

Answer 1

mean = 40
standard deviation = 8
observation = 48

start by finding the Zscore for the observation 48

Answer 2

To calculate z-score use the formula (point - mean)/standard deviation. So you get (48-40)/8 which equals a z-score of 1. Which makes sense because 48 is one standard deviation away from 40. So roughly 16% of students will take longer than 48 minutes meaning roughly 84% of students will finish the test before 48 minutes.

Answer 3

thanks