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OpenStax, Statistics §6.2 Using the Normal Distribution · Exercise 28 · Statistics · Normal distribution

Using the Normal Distribution · Exercise 28

In the 1992 presidential election, Alaska’s 40 election districts averaged 1,956.8 votes per district for a candidate. The standard deviation was 572.3. There are only 40 election districts in Alaska. The distribution of the votes per district for the candidate was bell-shaped. Let X = number of votes for the candidate for an election district.

(a) State the approximate distribution of X.
(b) Is 1,956.8 a population mean or a sample mean? How do you know?
(c) Find the probability that a randomly selected district had fewer than 1,600 votes for the candidate. Sketch the graph, and write the probability statement.
(d) Find the probability that a randomly selected district had between 1,800 and 2,000 votes for the candidate.
(e) Find the third quartile for votes for the candidate.

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OpenStax, Statistics · §6.2 Using the Normal Distribution · Exercise 28

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