Grade 8: Statistics & Bivariate Data — Comprehension Quiz

Multiple Choice Questions

1. Before 8th grade, the study of statistics has mostly focused on what type of data?
A. Bivariate data
B. Categorical data only
C. Univariate data
D. Two-way frequency data

2. Which of the following is NOT listed as a pattern of association students should be able to describe in a scatter plot?
A. Clustering
B. Outliers
C. Positive or negative association
D. Standard deviation

3. According to the standards, what is a straight line commonly used for when analyzing bivariate data?
A. Determining the sample space
B. Modeling relationships between two quantitative variables
C. Calculating relative frequencies
D. Organizing categorical data

4. In the biology experiment example from the standards, what does a slope of 1.5 cm/hr represent?
A. 1.5 cm of height regardless of sunlight
B. An additional hour of sunlight is associated with an additional 1.5 cm in mature plant height
C. The total height of the plant after 1.5 hours
D. The y-intercept of the linear model

5. What tool is used to summarize data on two categorical variables collected from the same subjects?
A. Scatter plot
B. Line of best fit
C. Two-way frequency table
D. Prediction function

6. In the curfew/chores example, what are researchers trying to determine?
A. The average age students get a curfew
B. Whether there is evidence of an association between having a curfew and having assigned chores
C. The total number of students with chores
D. The slope of a linear model

7. Which term from the Academic Vocabulary list refers to data with two variables?
A. Univariate data
B. Bivariate data
C. Random variables
D. Sample space

8. In the tomato/garden example (Mathematical Practice: Make Sense of Problems), what are students trying to determine?
A. The cost of growing tomatoes
B. Whether there is an association between liking tomatoes and having a garden at home
C. The best recipe for tomatoes
D. The slope of a linear model for tomato growth

Short Answer Questions

9. In the oil changes/car repair cost example, students plot data, write a prediction function in slope-intercept form, and then use it to make a prediction. Explain what a "prediction function" is used for in this context.

10. List at least three terms from the Academic Vocabulary section that relate specifically to the strength or type of association shown in a scatter plot.

11. Explain, in your own words, what students are expected to do when they "informally fit a straight line" to a scatter plot and "informally assess the model fit."

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Answer Key

1. C — Univariate data
2. D — Standard deviation
3. B — Modeling relationships between two quantitative variables
4. B — An additional hour of sunlight is associated with an additional 1.5 cm in mature plant height
5. C — Two-way frequency table
6. B — Whether there is evidence of an association between having a curfew and having assigned chores
7. B — Bivariate data
8. B — Whether there is an association between liking tomatoes and having a garden at home

1. A prediction function is a linear equation (in slope-intercept form) derived from bivariate data that can be used to predict a value (e.g., cost of repairs) for a given input (e.g., number of oil changes) not necessarily already in the data set.

1. Any three of: positive association, negative association, no apparent association, linear association, non-linear association, weak association, strong association, perfect association, cluster, outlier.

1. Students should describe drawing a straight line by eye/estimation that appears to best represent the trend in a scatter plot showing a linear association, and then judging how close the data points are to that line to assess how well the line models the data.