Unit 2 - Review 1

A random sample of 1,092 people were asked whether color was a consideration in buying a new car. They were also asked to identify one additional feature that was important. The responses are shown in the table. Which of the following is closest to the proportion of people who responded no to color consideration and who identified safety as the additional feature that was important?

• 0.18

• 0.34

• 0.36

• 0.49

• 0.51

Each accountant at a large accounting firm was classified according to accountant level (junior or senior) and method of transportation to work (walk, bus, drive alone, or carpool). The responses of the 320 accountants at the firm are summarized in the table. What proportion of the accountants at the firm are at the senior level and carpool to work?

• 20/60

• 20/72

• 20/320

• 112/320

• 132/320

First-year students enrolled at a college were asked whether they play video games. The responses, classified by whether the students were enrolled in the school of sciences or the school of arts, are shown in the table. Of all the students enrolled in the school of arts who responded, approximately what proportion responded that they play video games?

• 0.242

• 0.401

• 0.438

• 0.554

• 0.605

The table shows several values of x and their corresponding values of y. Which of the following is closest to the correlation between x and y?

• -0.98

• -0.95

• 0.20

• 0.95

• 0.98

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 month pounds

For a random sample of 20 professional athletes, there is a strong, linear relationship between the number of hours they exercise per week and their resting heart rate. For the athletes in the sample, those who exercise more hours per week tend to have lower resting heart rates than those who exercise less. Which of the following is a reasonable value for the correlation between the number of hours athletes exercise per week and their resting heart rate?

• 0.71

• 0.00

• -0.14

• -0.87

• -1.00

A tennis ball was thrown in the air. The height of the ball from the ground was recorded every millisecond from the time the ball was thrown until it reached the height from which it was thrown. The correlation between the time and height was computed to be 0. What does this correlation suggest about the relationship between the time and height?

• There is no relationship between time and height.

• There is no linear relationship between time and height.

• The distance the ball traveled upward is the same as the distance the ball traveled downward.

• The correlation suggest that there is measurement or calculation error.

• The correlation suggests that more measurements should be taken to better understand the relationship.

An experiment was conducted to investigate the relationship between the dose of a pain medication and the number of hours of pain relief. Twenty individuals with chronic pain were randomly assigned to one of five doses—0.0, 0.5, 1.0, 1.5, 2.0—in milligrams (mg) of medication. The results are shown in the scatterplot below. The data were used to fit a least-squares regression line to predict the number of hours of pain relief for a given dose. Which of the following would be revealed by a plot of the residuals of the regression versus the dose?

• The sum of the residuals is less than 0.

• The sum of the residuals is greater than 0.

• There are outliers associated with the lower doses.

• The variation in the hours of pain relief is not the same across the doses.

• There is a positive linear relationship between the residuals and the dose.

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.

Data were collected on two variables, x and y, to create a model to predict y from x. A scatterplot of the collected data revealed a curved pattern with a possible cubic relationship (y=ax^3, where a is a constant) between the variables. Which of the following transformations would be most appropriate for creating linearity between the variables?

• Taking the cube of y

• Taking the cube root of y

• Taking the cube root of both x and y

• Taking the log of y

• Taking the log of both x and y