AP Stats exam review - Quiz 1

A set of test scores has the following 5-number summary:

Which statement about outliers must be true?

• There is exactly one outlier on the lower end

• There is at least one outlier on the lower end

• There is exactly one outlier on the higher end

• There is at least one outlier on the higher end

• There are no outliers

The table above shows the regression output for predicting the number of calories from the number of milligrams of sodium for items at a fast-food chain. What percent of the variation in calories is explained by the regression model using sodium as a predictor?

• 7.36%

• 54.2%

• 53.8%

• 73.4%

• 73.6%

Tags

CCSS.8.SP.A.3

Researchers in the Southwest are studying tortoises—a species of animal that is affected by habitat loss due to human development of the desert. A total of 78 tortoises are being studied by researchers at several sites. The data on gender and species of all these tortoises is organized in the table shown below.

If a tortoise from this study is to be selected at random, let A = the tortoise is female and B = the tortoise is a Morafka. Which of the following appropriately interprets the value of P(B|A)?

• 31.3%

• 19.2%

• 55.6%

• 61.5%

Tags

CCSS.HSS.CP.B.6

The midterm scores for a statistics course were approximately normally distributed with a mean of 52 points and a standard deviation of 4 points. The final exam scores were approximately normally distributed with a mean of 112 points and a standard deviation of 10 points. One student had a score of 58 points on the midterm. If she had the same standardized score (z-score) on the final exam, what must her score have been?

• 15 points

• 58 points

• 118 points

• 122 points

• 127 points

Tags

CCSS.HSS.ID.A.4

Semir rolls a six-sided die every morning to determine what he will have for breakfast. If he rolls a 1 or 2, he takes time to cook himself a big breakfast. If he rolls a 3 or larger he grabs a quick lighter breakfast. When he cooks himself a big breakfast, there is a 15% chance he will be late for school. If he has a lighter breakfast, there is a 6% chance he will be late for school. What is the probability Semir will be on time for school any given day?

• 0.09

• 0.21

• 0.80

• 0.91

• 0.94

In a large high school, the student council wants to select a sample to survey the student body. They will first select 25 freshmen, then select 25 sophomores, then 25 juniors, and then finally 25 seniors. This is an example of a

• cluster sample

• stratified sample

• simple random sample

• convenience sample

• systematic sample

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A polling company wants to estimate, using a 95% confidence interval, the proportion of likely voters that would vote for a particular candidate in the upcoming presidential election. Of the following choices, which is the smallest sample size that will ensure a margin of sampling error less than or equal to 2 percentage points?

• 250

• 950

• 1150

• 2250

• 2401

Tags

CCSS.HSS.IC.B.4

Players in the National Football League weigh, on average, about 248 pounds with a standard deviation of about 47 pounds. If four players are to be selected at random, the expected value of the random variable W, the total combined weight of the four players, is 992 pounds. The standard deviation of W is approximately

• 47 lbs

• 67 lbs

• 94 lbs

• 141 lbs

• 188 lbs

When a patient complains to the doctor about a certain set of symptoms, the doctor diagnoses the patient with Condition A 15% of the time. If a patient with these symptoms is diagnosed with Condition A, he or she is diagnosed with Condition B 70% of the time. A patient with these symptoms that is not diagnosed with Condition A is diagnosed with Condition B 10% of the time. What is the probability that a patient with this set of symptoms will be diagnosed with at least one of these conditions?

• 0.235

• 0.250

• 0.765

• 0.850

• 0.950

Tags

CCSS.HSS.CP.B.7

A doctor hopes that a new surgery technique will shorten the recovery time compared to the standard technique. To test this, he designed an experiment in which patients who required this type of surgery were randomly assigned to the standard technique or the new technique. Then the mean recovery time for each treatment group was compared. Assuming conditions for inference were met, which analysis should be used?

• A t-test for a mean

• A t-test for a difference in means

• A z-test for a mean

• A z-test for a difference in means

• A z-test for a difference in proportions