# 8th Grade Math : Data

## Example Questions

### Example Question #1 : Data

The scatter plot provided displays a group of students' test scores versus the number of missing assignments the students have. Based on plot, select the best answer that describes the direction of the points.

A negative, linear association

A positive, nonlinear association

A positive, linear association

A negative, non linear association

A negative, linear association

Explanation:

The data points in the scatter plot move up the y-axis as the x-axis decreases; thus the data points show a negative association. Also, the data points do not curve, or go up and down, but gradually decreased; thus the scatter plot shows a linear association. We could even draw a "best fit" line:

### Example Question #2 : Data

A teacher at a high school conducted a survey of seniors and found that  students owned a laptop and  of those students also had a car. There were  students that did not have a laptop, but owned a car. Last, they found that  students did not own a laptop nor a car. Given this information, how many students had a laptop, but did not own a car?

Explanation:

To help answer this question, we can construct a two-way table and fill in our known quantities from the question.

The columns of the table will represent the students who have a laptop or do not have a laptop and the rows will contain the students who have a car or do not have a car. The first bit of information that we were given from the question was that  students had a laptop; therefore,  needs to go in the "laptop" column as the row total. Next, we were told that of those students,  owned a car; therefore, we need to put  in the "laptop" column and in the "car" row. Then, we were told that  students do not own a laptop, but own a car, so we need to put  in the "no laptop" column and the "car" row. Finally, we were told that  students do not have a laptop or a car, so  needs to go in the "no laptop" column and "no car" row. If done correctly, you should create a table similar to the following:

Our question asked how many students have a laptop, but do not own have a car. We can take the total number of students that own a lap top, , and subtract the number of students who have a car,

This means that  students who have a laptop, don't have a car.