AP Stats Unit 3 Review

Edwina is interested in how many snacks a person eats while binge-watching shows on a streaming channel. She randomly assigns 20 volunteers to five different times of binge-watching their favorite show: 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours. During the shows, she provides snacks and records the number of snacks eaten for each subject.

• The explanatory variable is the type of snack eaten by each subject and it is categorical.

• The explanatory variable is the type of show watched by each subject and it is categorical.

• The explanatory variable is the hours spent binge-watching a show by each subject and it is quantitative.

• The explanatory variable is the number of snacks eaten by each subject and it is quantitative.

• The explanatory variable is the number of snacks eaten each hour spent watching a show by each subject and it is quantitative.

Tags

CCSS.8.SP.A.4

A group of high school students is interested in understanding how the number of hours they spend on social media per week affects their GPA. They conduct a study and find the correlation coefficient between these two variables to be -0.8 with the following linear regression model: Which of the following is an incorrect statement?

• A) The direction of the association between GPA and hours on social media is negative.

• B) The least-squares regression line accounts for 64% of the variability in GPA.

• C) The least-squares regression line captures 80% of the observed hours on social media.

• D) Higher values for hours spent on social media per week tend be paired with lower values of GPA.

• E) The strength of the association between GPA and hours on social media is strong.

Tags

CCSS.8.SP.A.3

Which of the following values is closest to the correlation between the two variables shown in the scatterplot?

• -0.7

• -0.4

• 0

• 0.4

• 0.7

Tags

CCSS.HSS.ID.C.8

An AP Psychology teacher at a large high school is conducting a study on the relationship between the time (in minutes) it takes his students to complete a vocabulary quiz and the grade on the quiz. He believes that the more time a student takes on the quiz, the lower their grade will be. He randomly selects 10 AP Psychology students from the school and records the time they spent on the quiz and their score on the quiz. The results are shown. Which of the following is the equation of the least-squares regression line?

• A) Time = 119.4 - 1.59 (Score)

• B) Score = 1.59 + 119.4 (Time)

• C) Score = 119.4 - 1.59 (Time)

• D) Score = 119.4 + 7.78 (Time)

• E) Time = 1.59 + 119.4 (Score)

Tags

CCSS.HSS.ID.C.8

A local real estate agent is investigating the relationship between the distance from the city center, in miles, and the number of bedrooms in homes in a large city. Data from a random sample of 8 homes in the large city is displayed in the scatterplot, with accompanying least-squares regression line. Five of the observations are labeled A through E. Which observation has the smallest absolute value of the residual?

• A

• B

• C

• D

• E

Tags

CCSS.HSS.ID.B.6B

A statistics class did a “Barbie Bungee” activity and collected data on the number of rubber bands tied to a Barbie doll and the vertical distance the doll dropped (in centimeters) from a given height. The data were used to create the residual plot and regression output shown.

Which of the following is closest to the actual distance dropped for the Barbie with 1 rubber band?

• 7

• 13

• 15

• 23

• 119

Tags

CCSS.HSS.ID.B.6A

A scatterplot shows the relationship between the number of absences and the GPA (on a 4-point scale) for a large number of high school students. If the point labeled A is removed, which of the following statements would be true?

• The slope of the least-squares regression line would decrease and the strength of the association would increase.

• The slope of the least-squares regression line would decrease and the strength of the association would decrease.

• The slope of the least-squares regression line would increase and the strength of the association would remain the same.

• The slope of the least-squares regression line would increase and the strength of the association would increase.

• The slope of the least-squares regression line would increase and the strength of the association would decrease.

For an AP Statistics project, three students purchased 20 of the same kind of tealight candle. They set up four identical fans and set them varying distances away (5 feet, 10 feet, 15 feet, 20 feet) from the candles. They lit the candles, turned on the fans, and measured how long (in minutes) before each candle flame disappeared. The correlation between distance and minutes was found to be r = 0.93, and summary statistics are shown in the table below.

• ŷ = -0.23 + 6.31x

• ŷ = 157.63 + 6.31x

• ŷ = 76.99 + 0.14x

• ŷ = 1.72 + 0.14x

• ŷ = 72.08 + 5.86x

Tags

CCSS.HSS.ID.C.8

A small city in North Carolina is investigating the growth of the population since the year 2000. They record the population (in thousands), for each year since 2000. A scatterplot (not shown) revealed a curved pattern, so the city took the common logarithm of the population, in thousands, for each year. The regression output shows the results for predicting log(population) from the years since 2000. Which of the following is closest to the predicted number of people, in thousands, in the year 2020?

• 100,000

• 371,500

• 257,000

• 40,900

• 39,430

Tags

CCSS.HSS.ID.B.6A

A study measured two quantitative variables, X and Y, for a random sample of 50 individuals. An analyst fit two different regression models, Model 1 and Model 2, to the data. The regression equation and residual plot for each model are shown below. Which of the following conclusions is correct?

• Model 1 is appropriate, because the association between x and y is linear.

• Model 1 is appropriate, because the association between ln(x) and y is linear.

• Model 1 is appropriate, because the association between ln(x) and y is non-linear.

• Model 2 is appropriate, because the association between x and y is linear.

• Model 2 is appropriate, because the association between x and ln(y) is linear.

Tags

CCSS.HSS.ID.B.6A