 Search the Knowledgebase |
 Browse by Category |
|
|
|
| How can I create a RMA (reduced major axis) fit curve? |
| User Opinions |
0%
100%
|
|
Thank you for rating this answer.
|
Grapher 9’s fit curves use the least squares fit method. Grapher does not have an automatic way to create the reduced major axis regression equation directly. However, RMA and least squares fit curves are related. There is a script available that does calculate the RMA equation and add it to your existing graph as a function plot.
The downside to this method is that there is not a reported R2 value for the fit. However, some literature says that the R2 value is the same for the RMA fit as it is for the least squares fit method. So, if you create a line/scatter plot and add the Linear fit, the statistics for the linear fit are the same as the statistics for the RMA fit. You can then run the script to add the RMA fit curve to the graph.
To add an RMA (reduced major axis) fit to your graph:
- Create a 2D line/scatter plot from your data set using the Graph | 2D XY Graphs | Line/Scatter command.
- In Grapher 9, click the Edit | Script Recorder | Run command. Select the attached script and click Open. The RMA curve is added to the graph.
- To get the R2 statistic, select the line/scatter plot and click the Fits command in the Property Manager. Select Linear, Y=B*X+A and click Add. Click OK.
- Click on the fit curve and press the Report command to view the statistics. You can then copy the R2 value out of the report and paste it onto the graph.
|
| Visitor Comments |
|
No visitor comments posted. Post a comment
|
Print this page
Email this page
Post a comment