Back to Fit data to a normal distribution — Problem 5 · Task Set 4

Exercises: Fitting Data to a Normal Distribution

Work through each section in order. For empirical-rule problems, use the 68-95-99.7 percentages and the curve's symmetry. For z-score problems, first standardize with $z = \frac{x - \text{mean}}{\text{SD}}$, then look up the area with a calculator, spreadsheet, or table. Round percentages as directed. Remember: the empirical rule and z-scores apply ONLY to roughly normal data.

Grade 10·21 problems·~35 min·Common Core Math - HS Statistics and Probability·group·hss-id-a-4
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A

Fluency Practice

Use the empirical rule and z-scores. Test scores below are normal with mean 500, SD 100.

1.

Test scores are normal with mean 500500, SD 100100. For a score of x=650x = 650, the z-score is z=1.5z = 1.5. Using a calculator, spreadsheet, or table, the area BELOW z=1.5z = 1.5 is about 0.93320.9332. About what percentage of scores are ABOVE 650650? Round to the nearest tenth of a percent.