Output options with Prism

spa

s	Nonlin with Prism
	Initial values
	Fixing constants
	Method options
	Output options
	Default options
	Importing equations
	Writing equations
	Constraining
	Two models in one
	Simulate a curve

Interpreting the results

Comparing two curves

Distributions of best-fit values

curvefit.com was created by GraphPad Software, Inc. Send comments or questions to the author of these pages, Dr. Harvey Motulsky, president of GraphPad Software.

In April 2003, GraphPad released Prism 4 and published Fitting Models to Biological Data using Linear and Nonlinear Regression. This book includes all the information that comprises curvefit.com, and much more. You can read this book as a pdf file.

Output options with Prism

Include in tabular output

Choose which parts of the output you wish to see. We recommend that you leave all the boxes checked to get the most complete output.

Number of significant digits

Choose the number of significant digits used to report results. This is especially useful if you embed the results table on a graph or layout.

Range of X values and number of line segments

After determining the best-fit values of the variables in the equation, Prism calculates and plots the best-fit curve. It automatically plots the curve starting at the X position of the first (lowest X) data point and ends at the last data point. You may enter different limits.Curves are defined by many short line segments. You decide how many segments Prism will create. Prism initially creates all curves with 150 line segments. Increasing the number may improve the accuracy of standard curve calculations and make the curve appear smoother (especially if it has many inflection points).

Summary table and graph

When analyzing several data sets, the results table is rather lengthy. To display key results on a summary table, check the option box to create a summary table and select the variable you wish to summarize. Prism creates a summary table (as an additional results view) that shows the best-fit value of that variable for each data set, and graphs this table. Depending on your choices in the dialog, this may be a bar graph or an XY graph. It shows the best-fit value of a selected variable for each data set on the table. In some cases, you may analyze the summary table with linear or nonlinear regression. For example, the summary graph may show the best-fit value of a rate constant as a function of concentration (obtained from the column titles of the original data). You can fit a line or curve to that graph.Warning. When Prism compares the fits of two equations, it shows only the results for the second equation. Since this may not be helpful, we suggest that you only make summary tables when fitting a single equation.