AP Statistics Exam Review #1

Which of the following is a categorical variable?

• The weight of an automobile

• The time required to complete the Olympic marathon.

• The brand of shampoo purchased by shoppers at a grocery store.

• The fuel efficiency (in miles per gallon) of a hybrid car.

• The closing price of a particular stock on the New York Stock Exchange.

Tags

1.B

The school board in a certain school district obtained a random sample of 200 residents and asked if they were in favor of raising property taxes to fund the hiring of more teachers. The resulting confidence interval for the population proportion of residents in favor of raising taxes was (0.183, 0.257). Which of the following is the margin of error for this confidence interval?

• 0.037

• 0.074

• 0.183

• 0.220

• 0.257

A state agency wants to survey 1500 registered voters about an upcoming election. The agency randomly selects 50 registered voters from each of the state's 30 senatorial districts. Which type of sample was selected by the state agency?

• Simple Random Sample

• Stratified Random Sample

• Cluster Sample

• Systematic Random Sample

• Convenience Sample

The distribution of the number of cars X parked in a randomly selected residential driveway on any night is given by the discrete probability distribution.

What is the expected value of X?

• 1.00

• 1.45

• 1.95

• 2.00

• 2.05

The following back-to-back stemplots compare the ages of players from two minor-league hockey teams, each with 25 players. Which of the following statements cannot be justified from the stemplots?

• Team A has the same number of players in their 30's as does Team B.

• The median age of both teams is the same.

• Both age distributions are slightly skewed to the right.

• The range is greater for Team A.

The distribution of grade point averages (GPA's) for a certain college is approximately Normal with a mean of 2.5 and a standard deviation of 0.6. Any student with a GPA less than 1.0 is put on probation, while students with a GPA of 3.5 or higher is added to the dean's list. About what percentage of students at the school are on probation or on the dean's list?

• 0.6

• 4.7

• 5.4

• 94.6

• 95.3

• The approximate sampling distribution would be more variable.

• The approximate sampling distribution would be less variable.

• The approximate sampling distribution would have more dots.

• The approximate sampling distribution would have fewer dots.

• The approximate sampling distribution would be centered at 0.5.

A survey of 100 high school students was conducted. Each member of the sample was asked two questions: "Are you in 12th grade?" and "Do you have a driver's license, a learner's permit, or neither?" Overall, 23 members of the sample were in 12th grade. Also, 33 members of the sample had a driver's license and 12 had a permit.

Assuming there is no association between grade and driving status in the population of high school students, what is the expected number of 12th graders with a driver's license?

• 7.59

• 15.41

• 25.41

• 56

• Impossible to determine without more information.

Do hummingbirds prefer store-bought food made from concentrate or a mixture of sugar and water? To find out, a researcher obtains 10 identical hummingbird feeders and fills 5, chosen at random, with store-bought food from concentrate and the other 5 with a mixture of sugar and water. The feeders are then randomly assigned to 10 possible hanging locations in the researcher's yard. After one week, the researcher records the amount of mixture remaining for each feeder. Which inference procedure should you use to test whether hummingbirds show a preference for store-bought food based on amount consumed?

• A one-sample z-test for a proportion

• A two-sample z-test for a difference in proportions

• A chi-square test for independence

• A two-sample t-test for a difference in means

• A matched pairs t-test for a mean difference

A random sample of 100 students from a large high school was surveyed about transportation to school. Students were asked to estimate the total amount of time (in minutes) it took them to get to school on a typical day and their method of transportation. The histograms summarize distribution of travel time for the 40 students who ride the bus and the 60 students with other forms of transportation?

a) Compare these distributions.

b) Is it possible that the median travel time is the same for both groups? Justify your answer.