AP Stat Unit 2 MCQ practice

At a large airport, data were recorded for one month on how many baggage items were unloaded from each flight upon arrival as well as the time required to deliver all the baggage items on the flight to the baggage claim area. A scatterplot of the two variables indicated a strong, positive linear association between the variables. Which of the following statements is a correct interpretation of the word “strong” in the description of the association?

• A least-squares model predicts that the more baggage items that are unloaded from a flight, the greater the time required to deliver the items to the baggage claim area.

• The actual time required to deliver all the items to the baggage claim area based on the number of items unloaded will be very close to the time predicted by a least-squares model.

• The time required to deliver an item to the baggage claim area is relatively constant, regardless of the number of baggage items unloaded from a flight.

• The variability in the time required to deliver all items to the baggage claim area is about the same for all flights, regardless of the number of items unloaded from a flight.

• The time required to unload baggage items from a flight is related to the time required to deliver the items to the baggage claim area.

Tags

CCSS.HSS.ID.B.6B

In a recent survey, high school students and their parents were asked to rate 60 recently released movies. The ratings were on a scale from 1 to 9, where 1 was “horrible” and 9 was “excellent”. For each movie, the average rating by the students and the average rating by their parents was calculated and the scatterplot below was constructed. The horizontal axis represents the student rating, and the vertical axis represents the parent rating. Thus, an individual data point would represent the rating of a single movie. Which of the following statements is justified by the scatterplot?

• The movies that the students liked the best also tended to be the movies that the parents liked the best, but the students tended to give lower scores.

• The movies that the students liked the best also tended to be the movies that the parents liked the best, but the students tended to give higher scores.

• The movies that the students liked the best also tended to be the movies that the parents liked the best, but each group tended to give the same scores.

• The movies that the students liked the best tended to be the movies that the parents liked the least, but the students tend to give lower scores.

• The movies that the students liked the best tended to be the movies that the parents liked the least, but the students tended to give higher scores.

Tags

CCSS.8.SP.A.1

Which of the following is the best description of a positive association between two variables?

• The values will create a line when graphed on a scatterplot.

• The values will create a line with positive slope when graphed on a scatterplot.

• As the value of one of the variables increases, the value of the other variable tends to decrease.

• As the value of one of the variables increases, the value of the other variable tends to increase.

• All values of both variables are positive.

Tags

CCSS.HSS.ID.B.5

Which of the following is the best description of the relationship displayed in the scatterplot?

• Negative, linear, and strong

• Positive, linear, and weak

• Negative, nonlinear, and strong

• Positive, nonlinear, and weak

• Positive, nonlinear, and strong

Tags

CCSS.HSS.ID.B.5

The scatterplot below displays the relationship between the percent change in the population of wolves and the moose density, in number of moose per square kilometer, over a 19-year period in a certain region. Notice that the association is negative, and that the points seem to be more spread out at higher moose densities. Suppose the variables on the scatterplot were reversed, so that moose density was the response variable on the vertical axis, and percent change in wolf population was the explanatory variable on the horizontal axis. Which of the following would be true?

• The association would still be negative, but the strength of the association would increase.

• The association would be positive, and the strength of the association would increase.

• The association would still be negative, but the strength of the association would decrease.

• The association would be positive, but the strength of the association would not change.

• The direction and strength of the association would not change

Tags

CCSS.8.SP.A.3

A botanist found a correlation between the length of an aspen leaf and its surface area to be 0.94. Why does the correlation value of 0.94 not necessarily indicate that a linear model is the most appropriate model for the relationship between length of an aspen leaf and its surface area?

• The value must be exactly 1 or -1 to indicate a linear model is the most appropriate model.

• The value must be 0 to indicate a linear model is the most appropriate model.

• A causal relationship should be established first before determining the most appropriate model.

• The value of 0.94 implies that only 88% of the data have a linear relationship.

• Even with a correlation value of 0.94, it is possible that the relationship could still be better represented by a nonlinear model.

Tags

CCSS.HSS.ID.B.6B

A researcher in Alaska measured the age (in months) and the weight (in pounds) of a random sample of adolescent moose. When the least-squares regression analysis was performed, the correlation was 0.59. Which of the following is the correct way to label the correlation?

• 0.59 months per pound

• 0.59 pounds per month

• 0.59

• 0.59 months times pounds

• 0.59 months pounds

Tags

CCSS.HSS.ID.C.8

A small business owner has created a linear regression model to predict the number of new customers who will visit a shop based on the number of times the owner has an advertisement played on the radio. What is the explanatory variable and what is the response variable?

• Explanatory: number of new customers; response: number of times the advertisement is played

• Explanatory: number of times the advertisement is played; response: number of new customers

• Explanatory: number of times the advertisement is played; response: number of purchases made by customers

• Explanatory: number of purchases made by customers; response: number of times the advertisement is played

• Explanatory: number of previous customers; response: number of new customers

Tags

CCSS.HSS.ID.C.9

Data were collected on the fiber diameter and the fleece weight of wool taken from a sample of 20 sheep. The data are shown in the following graphs. Graph 1 is a scatterplot of fleece weight versus fiber diameter with the respective least-squares regression line shown. Graph 2 is the associated plot of the residuals versus the predicted values. One point is circled on graph 1. Five points labeled A, B, C, D, and E are identified on graph 2. Which point on graph 2 represents the residual for the circled point on graph 1?

• A

• B

• C

• D

• E

Tags

CCSS.HSS.ID.B.6B

A roadrunner is a desert bird that tends to run instead of fly. While running, the roadrunner uses its tail as a balance. A sample of 10 roadrunners was taken, and the birds’ total length, in centimeters (cm), and tail length, in cm, were recorded. The output shown in the table is from a least-squares regression to predict tail length given total length. Suppose a roadrunner has a total length of 59.0 cm and tail length of 31.1 cm. Based on the residual, does the regression model overestimate or underestimate the tail length of the roadrunner?

• Underestimate, because the residual is positive.

• Underestimate, because the residual is negative.

• Overestimate, because the residual is positive.

• Overestimate, because the residual is negative.

• Neither, because the residual is 0.

Tags

CCSS.HSS.ID.B.6B