Unit 9: Bivariate Data · NY-8.SP.1, NY-8.SP.2, NY-8.SP.3, AI-S.ID.6, AI-S.ID.7
Both exams
Notes
Association language. Positive, negative, or none. Linear or nonlinear. Strong or weak. Outliers sit apart from the cloud. Correlation is not causation — Algebra I will make that explicit.
Interpreting the model. If ŷ = 2.4x + 31 models minutes of practice (x) and quiz score (y), the slope 2.4 means each additional minute of practice is associated with about 2.4 more points. The intercept 31 is the model’s predicted score with 0 minutes of practice — which may or may not make sense in the real world.
Vocabulary
line of best fit: A line that comes close to the data points and models the linear trend.
outlier: A data point that is unusually far from the overall pattern.
Practice (no calculator unless marked)
Nathan models sunflower height y (cm) against fertilizer x (grams) with the line of best fit y = 0.35x + 2. Based on the model, what does the slope of the line represent?
A. The height of the plant
B. The amount of fertilizer used
C. The average growth of the plant per gram of fertilizer used
D. The average amount of fertilizer used per centimeter the plant grew
The scatter plot of an alligator’s weight (pounds) versus growth time (weeks) is modeled by a line of best fit. Which statement best describes what the slope of that line represents?
A. The starting weight, in pounds, of the alligator.
B. The approximate number of pounds the alligator gains each week.
C. The maximum number of pounds the alligator gains each week.
D. The average number of pounds of food the alligator is fed each week.
Nathan models sunflower height y (cm) against fertilizer x (grams) with the line of best fit y = 0.35x + 2. Based on the model, what does the slope of the line represent?
A. The height of the plant
B. The amount of fertilizer used
C. The average growth of the plant per gram of fertilizer used
D. The average amount of fertilizer used per centimeter the plant grew
The scatter plot of an alligator’s weight (pounds) versus growth time (weeks) is modeled by a line of best fit. Which statement best describes what the slope of that line represents?
A. The starting weight, in pounds, of the alligator.
B. The approximate number of pounds the alligator gains each week.
C. The maximum number of pounds the alligator gains each week.
D. The average number of pounds of food the alligator is fed each week.
Nathan models sunflower height y (cm) against fertilizer x (grams) with the line of best fit y = 0.35x + 2. Based on the model, what does the slope of the line represent?
A. The height of the plant
B. The amount of fertilizer used
C. The average growth of the plant per gram of fertilizer used
D. The average amount of fertilizer used per centimeter the plant grew
The scatter plot of an alligator’s weight (pounds) versus growth time (weeks) is modeled by a line of best fit. Which statement best describes what the slope of that line represents?
A. The starting weight, in pounds, of the alligator.
B. The approximate number of pounds the alligator gains each week.
C. The maximum number of pounds the alligator gains each week.
D. The average number of pounds of food the alligator is fed each week.
Nathan models sunflower height y (cm) against fertilizer x (grams) with the line of best fit y = 0.35x + 2. Based on the model, what does the slope of the line represent?
A. The height of the plant
B. The amount of fertilizer used
C. The average growth of the plant per gram of fertilizer used
D. The average amount of fertilizer used per centimeter the plant grew
The scatter plot of an alligator’s weight (pounds) versus growth time (weeks) is modeled by a line of best fit. Which statement best describes what the slope of that line represents?
A. The starting weight, in pounds, of the alligator.
B. The approximate number of pounds the alligator gains each week.
C. The maximum number of pounds the alligator gains each week.
D. The average number of pounds of food the alligator is fed each week.