# Normal distribution - Probability

Suppose that the time required to complete a 1040R tax form is normally distributed with a mean of 100 minutes and a standard deviation of 20 minutes. What proportion of 1040R tax forms will be completed in less than 60 minutes? Round your answer to at least four decimal places.

© BrainMass Inc. brainmass.com October 2, 2020, 1:02 am ad1c9bdddfhttps://brainmass.com/statistics/probability/normal-distribution-probability-360519

#### Solution Preview

Mean = 100 minutes

Standard Deviation = 20 minutes

X = 60 minutes

Z score = (X-Mean)/Standard deviation = ...

#### Solution Summary

The solution shows how to calculate the probability using normal distribution.

$2.19