Worksheet

z-scores and normal probabilities

Grade 11 Math Worksheet - Challenge Me

NameDate

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

  1. z-table: an area of 0.9 to the left matches z = 1.28. Scores on Bo's class quiz are normal with mean 70 and SD 8. To the nearest tenth, what score marks the edge of the top 10%?

  2. z-table: an area of 0.05 to the left matches z = -1.645. Paper-airplane flights in Esme's class are normal with mean 150 cm and SD 20 cm. To the nearest tenth, what flight marks the edge of the bottom 5%?

  3. z-table: an area of 0.2 to the left matches z = -0.84. Puzzle times in Kira's class are normal with mean 12 minutes and SD 1.5 minutes. To the nearest tenth, what time marks the edge of the bottom 20%?

  4. A score of 62 on Luz's class test has a z-score of 2, and the mean is 50. What is the standard deviation?

  5. A 36-second lap in Milo's class has a z-score of -1.5, and the mean is 48 seconds. What is the standard deviation?

  6. A 7.5-hour flashlight in Pia's class has a z-score of 0.75, and the mean is 6 hours. What is the standard deviation?

  7. z-table (area to the left): z = 1.50: 0.9332. Ren helps weigh 500 eggs; the weights are normal with mean 60 g and SD 4 g. To the nearest whole number, about how many eggs are above 66 g?

  8. z-table (area to the left): z = 1.25: 0.8944. Tala helps weigh 800 apples; the weights are normal with mean 150 g and SD 16 g. To the nearest whole number, about how many apples are below 130 g?

  9. z-table (area to the left): z = 1.20: 0.8849. Ari reads a test of 1,200 bottles; the fills are normal with mean 500 mL and SD 2.5 mL. To the nearest whole number, about how many bottles are above 503 mL?

  10. z-table (area to the left): z = 1.60: 0.9452. Bo times 400 runners; the mile times are normal with mean 10 minutes and SD 0.5 minutes. To the nearest whole number, about how many runners are below 9.2 minutes?

PencilGopencilgo.com

z-scores and normal probabilities

Answer Key - Grade 11 Math Worksheet - Challenge Me

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

  1. z-table: an area of 0.9 to the left matches z = 1.28. Scores on Bo's class quiz are normal with mean 70 and SD 8. To the nearest tenth, what score marks the edge of the top 10%?

    80.2

  2. z-table: an area of 0.05 to the left matches z = -1.645. Paper-airplane flights in Esme's class are normal with mean 150 cm and SD 20 cm. To the nearest tenth, what flight marks the edge of the bottom 5%?

    117.1

  3. z-table: an area of 0.2 to the left matches z = -0.84. Puzzle times in Kira's class are normal with mean 12 minutes and SD 1.5 minutes. To the nearest tenth, what time marks the edge of the bottom 20%?

    10.7

  4. A score of 62 on Luz's class test has a z-score of 2, and the mean is 50. What is the standard deviation?

    6

  5. A 36-second lap in Milo's class has a z-score of -1.5, and the mean is 48 seconds. What is the standard deviation?

    8

  6. A 7.5-hour flashlight in Pia's class has a z-score of 0.75, and the mean is 6 hours. What is the standard deviation?

    2

  7. z-table (area to the left): z = 1.50: 0.9332. Ren helps weigh 500 eggs; the weights are normal with mean 60 g and SD 4 g. To the nearest whole number, about how many eggs are above 66 g?

    33

  8. z-table (area to the left): z = 1.25: 0.8944. Tala helps weigh 800 apples; the weights are normal with mean 150 g and SD 16 g. To the nearest whole number, about how many apples are below 130 g?

    84

  9. z-table (area to the left): z = 1.20: 0.8849. Ari reads a test of 1,200 bottles; the fills are normal with mean 500 mL and SD 2.5 mL. To the nearest whole number, about how many bottles are above 503 mL?

    138

  10. z-table (area to the left): z = 1.60: 0.9452. Bo times 400 runners; the mile times are normal with mean 10 minutes and SD 0.5 minutes. To the nearest whole number, about how many runners are below 9.2 minutes?

    22