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Back to 7.2 The Central Limit Theorem for Sums (Optional)

7.2 Exercise 4

Avg difficulty 2.5

In a recent study reported Oct.29, 2012, the mean age of tablet users is 35 years. Suppose the standard deviation is 10 years. The sample size is 39.

  1. What are the mean and standard deviation for the sum of the ages of tablet users? What is the distribution?
  2. Find the probability that the sum of the ages is between 1,400 and 1,500 years.
  3. Find the 90th percentile for the sum of the 39 ages.

OpenStax Statistics, 7.2 The Central Limit Theorem for Sums (Optional), exercise 4

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