The normal curve and the empirical rule
Grade 11 Math Worksheet
Circle the best answer, or write your answer on the line.
Pia's class times a bike ride. The times are roughly normal, with mean 50 minutes and SD 6 minutes. What percent of the times are between 44 and 62 minutes?
Tala times how long the class's ice cubes take to melt. The times are roughly normal, with mean 12 minutes and SD 1.5 minutes. What percent of the times are below 10.5 minutes?
Zee measures the lengths of the class's paper chains. The lengths are roughly normal, with mean 40 cm and SD 4 cm. What percent of the lengths are between 40 and 48 cm?
Ari helps a farm weigh 400 apples. The weights are roughly normal, with mean 150 g and SD 10 g. About how many of the apples are between 140 and 160 g?
Bo's school records 200 students' jumps. They are roughly normal, with mean 150 cm and SD 20 cm. About how many of the jumps are above 190 cm?
Esme reads a factory test of 1,000 bulbs. Their lives are roughly normal, with mean 800 hours and SD 40 hours. About how many of the bulbs are between 800 and 880 hours?
Jun checks 500 bottles from a filling machine. The amounts are roughly normal, with mean 500 mL and SD 4 mL. About how many of the bottles are below 496 mL?
Kira's dot plot of wait times at the lunch line has most dots at 2 to 4 minutes and a long tail out to 15 minutes. Which describes the shape?
- Skewed right: the long tail is on the right
- Skewed left: the peak is on the left
- Symmetric: it has one peak and looks balanced
Luz's dot plot of class quiz scores has most dots at 85 to 95 points and a long tail down to 40 points. Which describes the shape?
- Skewed right: the peak is on the right
- Skewed left: the long tail is on the left
- Symmetric: it has one peak, so it looks balanced
Milo's dot plot of the pages read in a week is skewed right: most dots are low, and a few readers read far more. How do the mean and median compare?
- The mean is greater than the median
- The mean and median are equal
- The mean is less than the median