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In this module, we’ll be creating another scatter plot that examines the growth relationship
between the weight and age of fruit flies.
This will demonstrate polynomial regression.
After opening data file growth.sav, click on the graphs menu.
Scroll down to legacy dialogs, then select scatter dot.
Select the simple scatter option, then click the define button.
In here, select the variable weight and transfer it to the y-axis by clicking on the top transfer arrow button.
Click on the variable age and transfer it to the x-axis by clicking on the second transfer arrow button.
The weight will be our dependent variable and age our independent.
After you’re finished, click on the ok button.
In the output viewer window, click on the scroll bar then drag your mouse to reveal the entire graph.
As you can see, there is a definite relationship between the weight and age of fruit flies.
However, this is not a linear relationship.
You’ll see some curvature in the lines formed by the dots.
Let’s run a polynomial regression to better understand our findings.