# AP Statistics Free Response Example

1. The histogram below describes the heights of all 88 students that graduated from a New York City high school in 2010.

a) Describe quantitatively and qualitatively the distribution.
b) Estimate the 4th quartile as accurately as the histogram allows.
c) Give a possible reason for the bimodal nature of the distribution.

2. A media company plans to publish a special edition of a newspaper. Past experience shows that the number of newspapers the company will sell is described by the following table:

 Newspapers 210,000 to 220,000 220,001 to 230,000 230,001 to 240,000 240,001 to 250,000 250,001 to 260,000 260,001 to 270,000 270,001 to 280,000 280,001 to 290,000 Probability .01 .07 .14 .25 .24 .15 .1 .04

a) What is the probability that the company will sell less than 250,000 newspapers?
b) The cost of selling this special edition is \$100,000 for up to 260,000 newspapers and a flat cost of \$10,000 if more are sold. What is the expected sum the company will spend to sell the special edition?
c) Given that the company spends the flat extra cost of \$10,000, what is the probability that the company sells between \$270,000 and \$280,000 newspapers?

3. A large university conducts two tests to determine if the opinion of the students about global warming is influenced by recent weather.
The first test is given after 15 days of warmer than normal weather to a random sample of 90 students. Out of the 90 students, 73 responded that they are worried by global warming and 17 responded that they are not worried by global warming.
The second test is given after 15 days of colder than normal weather to a separate random sample of 96 students. Out of the 96 students, 74 responded that they are worried by global warming and 22 responded that they are not worried by global warming.
Does the test data provide evidence that the opinion of the students about global warming is influenced by recent weather?

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