8th Grade Unit 3 Test

1. Which is a true statement about two numerical sets of data that have negative association?

• A. As one variable increases, the other variable does not change.
• B. As one variable increases, the other variable increases.
• C. As one variable decreases, the other variable decreases.
• D. As one variable increases, the other variable decreases.

2. Which of the following is a true statement about scatter plots A and B?

• A. Only scatter plot A shows negative association.
• B. Scatter plot A appears to have outliers.
• C. Scatter plot B has a stronger association than A.
• D. Neither scatter plots show a linear association

3. Write an equation in slope-intercept form for the trend line shown on the scatter plot below.

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4. The scatter plot shows the number of days since several people filled their cars with gas and the gallons of gas in their tank. Which is the most reasonable estimate of the gallons of gas in a tank if it has been 3 days since filling up?

• A. 7 gallons
• B. 17 gallons
• C. 23 gallons
• D. 10 gallons

5. Which variables would the scatter plot below be most likely to represent?

• A. The number of siblings a person has and number of letters in their name.
• B. The number of guests at a hotel and the total water consumption
• C. The total number of miles driven and the total gallons of gas used
• D. The number of people at a concert and the total concession sales

6. Which scatter plot best represents the table?

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7. Which is true about the association seen in the data?

• A. There is no association.
• B. The association is positive and linear.
• C. The association is negative and linear.

8. Are there any outliers in the data from question #7?

• A. Yes; (93, 500) is an outlier since it is the greatest data point.
• B. Yes; (66, 250) is an outlier since it is the lowest data point.
• C. Yes; (88, 301) is an outlier since it does not fit the general trend of the data.
• D. No; there are not any outliers in the data.

9. Which of the following is NOT a true statement about the scatter plot?

• A. The association is positive.
• B. The association is linear.
• C. For every additional day of a trip, the weight of a suitcase increases 5 pounds.
• D. For every 5 additional days of a trip, the weight of a suitcase increases one pound.

10. Write and equation and use the equation to predict the weight of a suitcase for someone taking a 9-day trip. (plug 9 in for x in your equation)

• 75 pounds
• 60 pounds
• 50 pounds
• 80 pounds