Bluebook SAT Test Two-Variable Data: Models and Scatterplots 8

Question 1

A scatterplot displays data with the line y = 7x − 3. A point at x = 5 has actual y = 38. Is the actual y above or below the line, and what is the residual?

Accepted Answer

Above the line; residual = +6

Answer

Below the line; residual = −6

Answer

Above the line; residual = +3

Answer

Below the line; residual = −3

Question 2

If a linear model for x and y has slope 0 (a horizontal line), what does this imply about the correlation?

Accepted Answer

The correlation is 0; y does not change as x changes

Answer

The correlation is 1

Answer

The correlation is −1

Answer

The correlation is undefined

Question 3

Data on the amount of fertilizer used (x) and crop yield (y) shows the model y = −0.1x² + 5x + 20. For what value of x is the yield maximized?

Accepted Answer

25

Answer

50

Answer

20

Answer

5

Question 4

A company's revenue is modeled by y = 300(1.08)^x, where x is years since founding. What does 1.08 represent?

Accepted Answer

Revenue grows by 8% per year

Answer

Revenue grows by 108% per year

Answer

Revenue decreases by 8% per year

Answer

Revenue started at $1.08

Question 5

Two variables have a negative correlation. As x increases by 1, y changes by −4. The line of best fit has y-intercept 60. What is the equation?

Accepted Answer

y = −4x + 60

Answer

y = 4x + 60

Answer

y = −4x − 60

Answer

y = 60x − 4

Question 6

A table shows x: 0, 1, 2, 3 and y: 5, 15, 45, 135. What is the growth factor of this exponential model?

Accepted Answer

3

Answer

5

Answer

10

Answer

15

Question 7

A line of best fit for a dataset has the equation y = 2.2x + 1.5. Which of the following is closest to the predicted y when x = 7.5?

Accepted Answer

18

Answer

16.5

Answer

14

Answer

20