# plotDiagnostics

Plot observation diagnostics of generalized linear regression model

## Syntax

## Description

`plotDiagnostics`

creates a plot of observation
diagnostics, such as leverage and Cook's distance, to identify outliers and influential
observations.

`plotDiagnostics(`

creates a leverage
plot of the generalized linear regression model (`mdl`

)`mdl`

)
observations. A dotted line in the plot represents the recommended threshold
values.

`plotDiagnostics(`

specifies the graphical properties of diagnostic data points using one or more
name-value pair arguments. For example, you can specify the marker symbol and size
for the data points.`mdl`

,`plottype`

,`Name,Value`

)

returns graphics objects for the lines or contour in the plot using any of the input
argument combinations in the previous syntaxes. Use `h`

= plotDiagnostics(___)`h`

to modify
the properties of a specific line or contour after you create the plot. For a list
of properties, see Line Properties and Contour Properties.

## Examples

## Input Arguments

## Output Arguments

## More About

## Tips

The data cursor displays the values of the selected plot point in a data tip (small text box located next to the data point). The data tip includes the

*x*-axis and*y*-axis values for the selected point, along with the observation name or number.Use

`legend('show')`

to show the pre-populated legend.

## Alternative Functionality

A `GeneralizedLinearModel`

object provides multiple plotting functions.

When verifying a model, use

`plotDiagnostics`

to find questionable data and to understand the effect of each observation. Also, use`plotResiduals`

to analyze the residuals of the model.After fitting a model, use

`plotPartialDependence`

to understand the effect of a particular predictor. Also, use`plotSlice`

to plot slices through the prediction surface.

## References

[1] Neter, J., M. H. Kutner, C. J.
Nachtsheim, and W. Wasserman. *Applied Linear Statistical Models*,
Fourth Edition. Chicago: McGraw-Hill Irwin, 1996.

## Extended Capabilities

## Version History

**Introduced in R2012a**