The normal curve and the empirical rule

Answer Key - Grade 11 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Pia's class times a walk around the park. The times are roughly normal, with mean 50 minutes and SD 4 minutes. What percent of the times are between 50 and 54 minutes?

   34
2. 2.

   Ren measures the sunflowers in the school garden. The heights are roughly normal, with mean 160 cm and SD 8 cm. What percent of the heights are above 168 cm?

   16
3. 3.

   Zee times how long the class takes to finish a puzzle. The times are roughly normal, with mean 12 minutes and SD 2 minutes. What percent of the times are below 8 minutes?

   2.5
4. 4.

   Ari records how far paper airplanes fly in the gym. The distances are roughly normal, with mean 30 feet and SD 3 feet. What percent of the distances are above 39 feet?

   0.15
5. 5.

   Bo weighs bags of rice from a packing machine. The weights are roughly normal, with mean 500 grams and SD 10 grams. What percent of the weights are above 520 grams?

   2.5
6. 6.

   band percents left to right: 0.15, 2.35, 13.5, 34, 34, 13.5, 2.35, 0.15. Esme measures the class's long jumps. The jumps are roughly normal, with mean 75 inches and SD 6 inches. What percent of the jumps are between 69 and 75 inches?

   34
7. 7.

   Kira's class scores on a puzzle test are roughly normal, with mean 100 and SD 15. What value marks the top of the middle 95% of the values?

   130
8. 8.

   The heights of the bean plants in Luz's class are roughly normal, with mean 64 cm and SD 3 cm. What value marks the bottom of the middle 68% of the values?

   61
9. 9.

   The times for Milo's class to run a lap are roughly normal, with mean 20 seconds and SD 2.5 seconds. What value marks the top of the middle 99.7% of the values?

   27.5
10. 10.

    In Noah's class test, the hours a flashlight runs are roughly normal, with mean 8 and SD 0.5. What value marks the bottom of the middle 95% of the values?

    7