Writing an equation of a curve or line on the graph

Prism does not automatically write equations on the graph. You can see the numerical results of linear or nonlinear regression by going to the appropriate page in the Results folder.

Linear regression

Prism 6 or later: The equation is written out at the bottom of the results page. Copy that and paste onto the graph.

Older versions: You can write the equation using the text tool...

For example, if the slope is 2.3 and the intercept is 4.5, write:

 Y = 4.5 + 2.3X

Nonlinear regression: Equation editor

Prism shows you the best-fit values of all the parameters as well as the form of the equation, and Prism Help shows you all the built-in equations in a general form. But you'd need to use the equation editor to put the equation on your graph. 

If Microsoft Equation Editor is installed on your system, you will see a quick-access button on your toolbar when you are on either a graph or a layout sheet:

Here is an example of a generic equation:

 

Some users wish to write the substituted form of an equation, with the actual fitted values for the parameters. For all but the simplest equations, this may be a bit awkward:

 

 

 

More on writing equations.

Nonlinear regression: Embedded table

A better way might be to simply show the parameter values from the curve of best fit in tabular form. Copy selected results and then paste onto a graph. This will paste a linked embedded object:

 

This is particularly helpful when you're working with templates--if you want to do the same analysis repeatedly with different data each time. Whenever you change your data, both the line or curve and the embedded talbe will update automatically. 

Cubic spline

Cubic spline fits a different model to the space between every pair of points, so there is no possibility to write out the curve as a compact equation.