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OpenStax, Introductory Statistics 2e §6.2 Using the Normal Distribution · Exercise 30 · Statistics · Normal distribution

Using the Normal Distribution · Exercise 30

A motorcycle racer averages 129.71 seconds per 2.5 mile lap (in a seven-lap race) with a standard deviation of 2.28 seconds. The distribution of their race times is normally distributed. We are interested in one of their randomly selected laps.

(a) In words, define the random variable X.
(b) X ~ _____(_____,_____)
(c) Find the percent of the racer's laps that are completed in less than 130 seconds.
(d) The fastest 3% of the racer's laps are under _____.
(e) The middle 80% of the racer's laps are from _______ seconds to _______ seconds.

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OpenStax, Introductory Statistics 2e · §6.2 Using the Normal Distribution · Exercise 30

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