- To analyze the relationship, it is recommended to sketch a line between the dots and look at the line instead of the dots.
- When you interpret a scatterplot, look at the data as you go from left to right.
Scatterplots can visualize the following features of the relationships:
1. The type of the correlation between the variables- positive or negative correlation or no correlation:
In positive correlation, as one variable increases so does the other. In a positive correlation the slope of the line is positive.
In negative correlation, as one variable increases the other decreases. In a negative correlation the slope of the line is negative.
2. The type of the data pattern- linear (straight) or nonlinear (curved):
A linear correlation can be graphed as a straight line in the xy-plane. The slope of a linear line is constant all the way along the line.
A curved correlation can be graphed as a smooth line that changes its direction at least once. The slope of a curved line is constantly changing.
3. The strength of the relationship between the variables:
The more concentrated the dots are along the line or the curve, the stronger the relationship. In other words: if the points are close to the line or the curve, the relationship is considered as strong.
4. Unusual features in the data, such as gaps in the data set.