Final exam AP STAT

Scientists estimate that the distribution of the life span of the Galápagos Islands giant tortoise is approximately normal with mean 100 years and standard deviation 15 years. Based on the estimate, which of the following is closest to the age of a Galápagos Islands giant tortoise at the 90th percentile of the distribution?

• 80

• 115

• 120

• 125

• 130

For the purpose of determining the value of its end-of-year inventory, a clothing store creates a list at the end of the year of every item currently in stock along with each item’s wholesale price. Which of the following is the best description of the end-of-the-year activity?

• An experiment, because the items are treatments and wholesale prices are responses

• An experiment, because the store does not know the total wholesale price of all the items.

• A sample survey, because the store wants to estimate the value of all items for the entire year.

• A sample survey, because the items currently in the store at the end of the year are a random sample of all items in the store for the entire year.

• A census, because the wholesale prices of all items are listed.

A grocery store receives deliveries of corn from two farms, one in Iowa and the other in Ohio. Both farms produce ears of corn with mean weight 1.26 pounds. The standard deviation of the weights of the ears of corn from the farm in Ohio is 0.01 pound greater than that from the farm in Iowa. A randomly selected ear of corn from the farm in Iowa weighed 1.39 pounds, which has a standardized score of 1.645 for the distribution of weights for the Iowa corn. If an ear of corn from the farm in Ohio weighs 1.39 pounds, how many standard deviations from the mean is the weight with respect to the Ohio distribution?

• 1.46 standard deviations below the mean

• 1.46 standard deviations above the mean

• 1.65 standard deviations above the mean

• 1.88 standard deviations below the mean

• 1.88 standard deviations above the mean

Sean and Evan are college roommates who have part-time jobs as servers in restaurants. The distribution of Sean’s weekly income is approximately normal with mean $225 and standard deviation $25. The distribution of Evan’s weekly income is approximately normal with mean $240 and standard deviation $15. Assuming their weekly incomes are independent of each other, which of the following is closest to the probability that Sean will have a greater income than Evan in a randomly selected week?

• 0.067

• 0.159

• 0.227

• 0.303

• 0.354

. According to data from the United States Elections Project, only 36 percent of eligible voters voted in the 2014 elections. For random samples of size 40, which of the following best describes the sampling distribution of pˆ, the sample proportion of people who voted in the 2014 elections?

• (A) The sampling distribution is skewed to the left, with mean 0.36 and standard deviation 0.076.

• (B) The sampling distribution is skewed to the right, with mean 0.64 and standard deviation 0.006.

• (C) The sampling distribution is approximately normal, with mean 0.36 and standard deviation 0.076.

• (D) The sampling distribution is approximately normal, with mean 0.36 and standard deviation 0.006.

• (E) The sampling distribution is approximately normal, with mean 0.64 and standard deviation 0.076.

At a certain restaurant, the distribution of wait times between ordering a meal and receiving the meal has mean 11.4 minutes and standard deviation 2.6 minutes. The restaurant manager wants to find the probability that the mean wait time will be greater than 12.0 minutes for a random sample of 84 customers. Assuming the wait times among customers are independent, which of the following describes the sampling distribution of the sample mean wait time for random samples of size 84 ?

• (A) Approximately normal with mean 11.4 minutes and standard deviation 2.6 minutes

• (C) Approximately normal with mean 12.0 minutes and standard deviation 2.6 minutes

• (D) Binomial with mean 84(0.41) minutes and standard deviation 84(0.41)(0.59) minutes

• (E) Binomial with mean 84(0.5) minutes and standard deviation 84(0.5)(0.5) minutes

• A

• B

• C

• D

• E

• A

• B

• C

• D

• E

• A

• B

• C

• D

• E

• A

• B

• C

• D

• E