Worksheet

z-scores and normal probabilities

Grade 11 Math Worksheet - Building Confidence

NameDate

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

  1. Dot plot of the class's values with the balance point 50 marked and one spread, 8, drawn as an arrow. Tala scores 62 on a class puzzle test with mean 50 and SD 8. What is the z-score of 62?

  2. Dot plot of the class's values with the balance point 56 marked and one spread, 5, drawn as an arrow. Ari's bean plant is 44 cm tall; the class's plants have mean 56 cm and SD 5 cm. What is the z-score of 44?

  3. Dot plot with the balance point 70 marked and one spread, 5, drawn as an arrow. Scores on Jun's class quiz have mean 70 and SD 5. What score has a z-score of 2?

  4. Paper airplanes in Kira's class fly a mean of 150 cm with SD 12 cm. What flight has a z-score of -1.5?

  5. Dot plot with the balance point 30 marked and one spread, 4, drawn as an arrow. Luz's class reads a mean of 30 pages a day with SD 4 pages. What page count has a z-score of 0.75?

  6. Milo checks a machine that fills rice bags with a mean of 500 g and SD 20 g. What fill has a z-score of -2.5?

  7. Noah's class puzzle scores are normal with mean 50 and SD 8. The z-score of 62 is 1.5. To four decimal places, what fraction of the scores are above 62?

  8. Bean plants in Pia's class have normal heights: mean 50 cm, SD 4 cm. A 44 cm plant has z = -1.5. To four decimal places, what fraction of the plants are below 44 cm?

  9. Ren's class jump heights are normal with mean 40 cm and SD 5 cm. The z-score of 51 cm is 2.2. To four decimal places, what fraction of the jumps are above 51 cm?

  10. Tala's class bike lap times are normal with mean 60 s and SD 5 s. The z-score of 56 s is -0.8. To four decimal places, what fraction of the times are below 56 s?

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z-scores and normal probabilities

Answer Key - Grade 11 Math Worksheet - Building Confidence

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

  1. Dot plot of the class's values with the balance point 50 marked and one spread, 8, drawn as an arrow. Tala scores 62 on a class puzzle test with mean 50 and SD 8. What is the z-score of 62?

    1.5

  2. Dot plot of the class's values with the balance point 56 marked and one spread, 5, drawn as an arrow. Ari's bean plant is 44 cm tall; the class's plants have mean 56 cm and SD 5 cm. What is the z-score of 44?

    -2.4

  3. Dot plot with the balance point 70 marked and one spread, 5, drawn as an arrow. Scores on Jun's class quiz have mean 70 and SD 5. What score has a z-score of 2?

    80

  4. Paper airplanes in Kira's class fly a mean of 150 cm with SD 12 cm. What flight has a z-score of -1.5?

    132

  5. Dot plot with the balance point 30 marked and one spread, 4, drawn as an arrow. Luz's class reads a mean of 30 pages a day with SD 4 pages. What page count has a z-score of 0.75?

    33

  6. Milo checks a machine that fills rice bags with a mean of 500 g and SD 20 g. What fill has a z-score of -2.5?

    450

  7. Noah's class puzzle scores are normal with mean 50 and SD 8. The z-score of 62 is 1.5. To four decimal places, what fraction of the scores are above 62?

    0.0668

  8. Bean plants in Pia's class have normal heights: mean 50 cm, SD 4 cm. A 44 cm plant has z = -1.5. To four decimal places, what fraction of the plants are below 44 cm?

    0.0668

  9. Ren's class jump heights are normal with mean 40 cm and SD 5 cm. The z-score of 51 cm is 2.2. To four decimal places, what fraction of the jumps are above 51 cm?

    0.0139

  10. Tala's class bike lap times are normal with mean 60 s and SD 5 s. The z-score of 56 s is -0.8. To four decimal places, what fraction of the times are below 56 s?

    0.2119