Scatter diagrams
The possible relationships between two variables are identified using scatter diagrams. In order to understand data as a whole, it is very important to understand the relationships among data elements. The steps to create a scatter diagram are:
1. Define the theoretical relationship: Relationships between variables are not always obvious. It is easy to assume the relationship between variables. The first step is to identify the two variables that will be examined.
2. Collect 50 to 100 paired samples of data: Analysis is based on a sufficient amount of data. Less data will result in erroneous conclusions.
3. Plot the data on x-y axis: The horizontal axis or x-axis should be used for independent variables. These variables are the base. If there is a relationship between the base and data of other variables, then when the base changes, the data of other variable also changes. The y-axis is used for the dependent variables. These variables will surely change if the base changes.
4. Interpret the data: Find regular patterns among the plotted points.
The figure shows example of scatter diagrams.
Figure: Scatter Diagram