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6.2 Exercise 12

Avg difficulty 2.5

In the United States the ages 13 to 55+ of smartphone users approximately follow a normal distribution with approximate mean and standard deviation of 36.9 years and 13.9 years respectively. Using this information, answer the following questions (round answers to one decimal place).

a. Calculate the interquartile range (IQR).

b. Forty percent of the smartphone users from 13 to 55+ are at least what age?

OpenStax Introductory Statistics 2e, 6.2 Using the Normal Distribution, exercise 12

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Adapted from Introductory Statistics 2e © 2023 Rice University. Licensed under CC BY 4.0. Source: Introductory Statistics 2e. Imported at revision 50ec917.