Question

Dave drives to work each morning at about the same time. His commute time is normally distributed with a mean of 47 minutes and a standard deviation of 5 minutes. What percentage of time is his commute less than 52 minutes?

Answer 1

0.15866

Explanation:

First, we calculate z-score

Mathematically;

z-score = value-mean/SD

here, mean = 47 , SD = 5 and value = 52

z-score = (52-47)/5 = 5/5 = 1

The probability we want to calculate is;

P(z<1) and we can access this from the standard score table

P(Z<1) =0.15866