Scatter Plot

To generate a Scatter Plot of any two quantitative data columns in the Pole Data Grid:

1. Select Statistics > Scatter from the Analysis ribbon.
2. The Scatter Plot dialog appears. Select the X Axis Data Column from the drop down. Only quantitative Pole Data Grid columns are available (i.e., Numeric Data Type).
3. Select the Y Axis Data Column from the drop down. Only quantitative Pole Data Grid columns are available (i.e., Numeric Data Type).
4. Optionally, select the Weighted checkbox to apply Terzaghi Weighting to Quantity (i.e., Quantity x Weight).
5. Optionally select the Show Regression Line checkbox to display the best-fit linear regression line.
6. Click OK to plot the scatter plot.

The Scatter Plot will be generated. At the bottom of the Scatter Plot, you will see a listing of the Correlation Coefficient, alpha and beta.

Correlation Coefficient

The Correlation Coefficient indicates the degree of correlation between the two variables plotted. The Correlation Coefficient can vary between -1 and 1. Numbers close to zero indicate a poor correlation, and numbers close to 1 or -1 indicate a strong correlation. Note that a negative correlation coefficient simply means that the slope of the best-fit linear regression line is negative.

Alpha and Beta

Alpha and Beta represent the y-intercept and slope, respectively, of the best-fit linear regression line to the scatter plot data. The linear regression line can be displayed on the plot by selecting the Show Regression Line option.

Regression Line

The Show Regression Line option is only applicable for Scatter Plots and can be used to toggle on or off the display of the best-fit linear regression line for a Scatter Plot.