Plot of slices through fitted nonlinear regression surface
plotSlice( creates a figure
containing one or more plots, each representing a slice through the regression
surface predicted by
mdl. Each plot shows the fitted response
values as a function of a single predictor variable, with the other predictor
variables held constant.
plotSlice also displays the 95% confidence bounds for the
response values. Use the Bounds menu to choose the type
of confidence bounds. Use the Predictors menu to select
which predictors to use for each slice plot. For details, see Tips.
Plot slices of a fitted nonlinear model.
reaction data and fit a model of the reaction rate as a function of reactants.
mdl = fitnlm(reactants,rate,@hougen,[1 .05 .02 .1 2]);
Create a slice plot.
X1 prediction line to the right, and observe the change in the predicted response
y and in the predicted response curves to
Use the Bounds menu in the figure window to choose the type of confidence bounds. You can choose Simultaneous or Non-Simultaneous, and Curve or Observation. You can also choose No Bounds to have no confidence bounds.
Simultaneous or Non-Simultaneous
Simultaneous (default) —
plotSlicecomputes confidence bounds for the curve of the response values using Scheffe's method. The range between the upper and lower confidence bounds contains the curve consisting of true response values with 95% confidence.
plotSlicecomputes confidence bounds for the response value at each observation. The confidence interval for a response value at a specific predictor value contains the true response value with 95% confidence.
Simultaneous bounds are wider than separate bounds, because requiring the entire curve of response values to be within the bounds is stricter than requiring the response value at a single predictor value to be within the bounds.
Curve or Observation
A regression model for the predictor variables X and the response variable y has the form
y = f(X) + ε,
where f is a function of X and ε is a random noise term.
Curve (default) —
plotSlicepredicts confidence bounds for the fitted responses f(X).
plotSlicepredicts confidence bounds for the response observations y.
The bounds for y are wider than the bounds for f(X) because of the additional variability of the noise term.
Use the Predictors menu in the figure window to select which predictors to use for each slice plot. If the regression model
mdlincludes more than eight predictors,
plotSlicecreates plots for the first five predictors by default.
Introduced in R2012a