Bluebook SAT Test Two-Variable Data: Models and Scatterplots 15

Question 1

A linear model for daily temperature (x, °F) and swimming pool attendance (y, people) is y = 5x − 150. On what temperature day does attendance equal 100 people?

Accepted Answer

50°F

Answer

Set 100 = 5x−150 → 5x=250 → x=50.

Question 2

Data shows sales (y) in thousands grow as y = 8(1.2)^x. After 3 years (x=3), what are predicted sales?

Accepted Answer

13.824 thousand

Answer

y = 8(1.2)^3 = 8 × 1.728 = 13.824 thousand.

Question 3

In a scatterplot, a point has a large positive residual. What does this mean?

Accepted Answer

The actual y value is much higher than the model predicted.

Answer

Residual = actual y − predicted y; a large positive residual means actual y >> predicted y.

Question 4

The line of best fit for data on advertising (x, $000) and revenue (y, $000) passes through (2, 50) and (8, 80). What is the slope?

Accepted Answer

5

Answer

Slope = (80−50)/(8−2) = 30/6 = 5.

Question 5

A model y = kx² fits a dataset. When x = 3, y = 36. What is the value of k?

Accepted Answer

4

Answer

36 = k(9) → k = 36/9 = 4.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Two-Variable Data: Models and Scatterplots 15