Two-Variable Data: Models and Scatterplots Flashcards
7 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Two-Variable Data: Models and Scatterplots flashcards as text
A scatterplot shows data modeled by y = 3x² + 2. What is the predicted value of y when x = 4?
Answer: 50
Substitute x=4: y = 3(16)+2 = 48+2 = 50.
In a linear model y = mx + b, the slope m is negative. Which of the following is true as x increases by 1?
Answer: y decreases by |m|
A negative slope means each unit increase in x causes y to decrease by the magnitude of m.
A scatterplot shows points (1, 4), (2, 7), (3, 10), (4, 13). Which equation fits this data exactly?
Answer: y = 3x + 1
Check slope: (7−4)/(2−1) = 3; y-intercept from (1,4): 4 = 3(1)+b → b=1. Equation: y=3x+1.
The line of best fit for data on weekly exercise hours (x) and resting heart rate (y, bpm) is y = −2.5x + 80. What does the −2.5 represent?
Answer: For each additional hour of exercise per week, the resting heart rate decreases by 2.5 bpm on average.
The slope −2.5 represents the average change in y (resting heart rate) per unit increase in x (weekly exercise hours).
A best-fit line passes through (0, 5) and (10, 25). What is the equation of this line?
Answer: y = 2x + 5
Slope = (25−5)/(10−0) = 20/10 = 2; y-intercept = 5 (given). Equation: y = 2x+5.
A scatterplot of x and y has r = −0.88. Which of the following best describes the relationship?
Answer: Strong negative linear relationship
r = −0.88 is close to −1, indicating a strong negative linear correlation.
Data shows a pattern y ≈ 4 · 2^x. Which model best describes this data?
Answer: Exponential
The form y = a · b^x is an exponential model; here a = 4 and b = 2 (the growth factor).