Creating a Scatter Plot

The scatter plot feature is useful to visualize the relationship between two variables in a dataset. The scatter plot can also be exported as an image file and saved to the local drive.

Screenshot

Note that it is important to manually save any time dependent information of the scatter plot when exporting the image file.

Summary Statistics

The histogram chart displays summary statistics when the visualization is created:

  1. The mean describes the variable average
  2. Standard deviation (σ) describes how dispersed the variable values are relative to the mean
  3. Pearson's product correlation coefficient (r) is the measure of a linear association between the plotted variables assuming a normal distribution.
  4. Spearman's rank correlation coefficient (ρ) is the measure of association between the ranks of the plotted variables. It is less sensitive to extreme values than the Pearson's product correlation coefficient.

Both Pearson's and Spearman's correlations ranges from -1 to 1, where linear association is stronger the closer r is to the range limits. If the correlation coefficient is positive, then an increase in one variable is associated with an increase in the other variable, while negative correlation coefficients indicate that as one variable increases, the other decreases. Correlation coefficients near 0 (positive or negative) suggest that there is little association, or correlation, between the two variables.

The same statistics are displayed for a subset selection in the same side bar, as shown in the example below. See Linking and Brushing for more insight.

Process Steps

  1. Select "Visualizations" in the main menu
  2. Select the "Scatter Plot" item
  3. A "Create a Scatter Plot" window will appear
  4. In the "Dataset" field, select the desired dataset from the Data panel you wish to visualize
  5. In the "X Variable" field, select the variable you wish to display on the horizontal axis
  6. In the "Y Variable" field, select the variable you wish to display on the vertical axis
  7. In the "Workspace" field, select the desired workspace tab to display the visualization
  8. Choose to display the visualization either in a new pane or to replace an existing visualization by selecting the corresponding pane
  9. Select "OK" to display the visualization