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OpenStax, Introductory Business Statistics 2e §7.1 The Central Limit Theorem for Sample Means · Exercise 4 · Statistics · Sampling distributions

The Central Limit Theorem for Sample Means · Exercise 4

Suppose that a category of world-class runners are known to run a marathon (26 miles) in an average of 145 minutes with a standard deviation of 14 minutes. Consider 49 of the races. Let the average of the 49 races.

(a) ~ _____(_____,_____)
(b) Find the probability that the runner will average between 142 and 146 minutes in these 49 marathons.
(c) Find the 80^th percentile for the average of these 49 marathons.
(d) Find the median of the average running times.

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OpenStax, Introductory Business Statistics 2e · §7.1 The Central Limit Theorem for Sample Means · Exercise 4

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