Mr. Wilcox spends a full day at Gingerman Raceway testing some new tires on his Honda
Civic. For 400 laps, he records his laptime in minutes. At the end of the day, he plots the
distribution of times and realizes that it follows an approximately normal distribution with
a mean of 1.84 and a standard deviation of 0.07.
1. Label the values 1, 2, and 3 standard deviations above and below the mean.
05D
-1 5D
1 SD
-2 SD
2 SD
-3 SD
3 SD
2. What percentage of the laptimes are less than 1.70 minutes?
3. What percentage of the laptimes are greater than 1.77 minutes?
4. What percentage of the laptimes are between 1.70 and 1.91 minutes?
5. What laptime would be in the slowest 2.5% of all laptimes?