1. Scatter Plots

2. Scatter plots
A graph of points which show the relationship between two quantitative variables measured on the same individual.
Such as…

3. Scatter plot vARIABLES
The x-axis value; it is the independent variable.
The y-axis value; it is the dependent variable.
RESPONSE
EXPLANATORY

4. So, which variable is which???
The explanatory variable is… The response variable is…
And what does the
graph tell you???

5. Scatter plots
Here you see a scatter plot… The explanatory variable is … The response variable is … As the x values increase, what is happening to the y values? This is an example of negative association.

6. Words which describe Scatter Plots
Strength
Strong—points follow a tight pattern.
Weak—points are scattered widely.
Form
Straight-line (linear)
Curved

7. Words which describe scatter plots
Positively Associated: As the x value goes up, the y value goes up; as the x value goes down, the y value goes down.
Negatively Associated: As the x value goes up, the y value goes down; as the x value goes down, the y value goes up.

8. How they look
Positively Associated
Negatively Associated

9. Homework This is due on Wed. 2/29-Thu. 3/1
Finish the lists of strong relationships and weak relationships.
Remember you will be choosing one from each list to use for your surveys.
This is due on
Wed. 2/29-Thu. 3/1