Distribution Fitter
Fit probability distributions to data
Description
The Distribution Fitter app interactively fits probability
distributions to data imported from the MATLAB® workspace. You can choose from 22 built-in probability distributions or
create your own custom distribution. The app displays plots of the fitted distribution
superimposed on a histogram of the data. Available plots include probability density
function (pdf), cumulative distribution function (cdf), probability plots, and survivor
functions. You can export the fitted parameter values to the workspace as a probability
distribution object, and use object functions to perform further analyses. For more
information on working with these objects, see Working with Probability Distributions. For the programmatic work flow of
the Distribution Fitter app, see distributionFitter
.
More
Required Products
MATLAB
Statistics and Machine Learning Toolbox™
Open the Distribution Fitter App
MATLAB Toolstrip: On the Apps tab, under Math, Statistics and Optimization, click the app icon.
MATLAB command prompt: Enter
distributionFitter
.
Parameters
Data
— Data to import from the workspace
list of variables | valid MATLAB expression
Specify the data to import by selecting a variable from the drop-down list. If the variable is a matrix, the app imports the first column of the matrix by default. To select a different column or row of the matrix, click Select Column or Row. Alternatively, you can enter any valid MATLAB expression in the field.
Censoring
— Variable containing censoring data
list of variables
Specify the censoring data by selecting a variable from the drop-down list. If the variable is a matrix, the app imports the first column of the matrix by default. To select a different column or row of the matrix, click Select Column or Row. This parameter is optional.
Frequency
— Variable containing frequency data
list of variables
Specify the frequency data by selecting a variable from the drop-down list. If the variable is a matrix, the app imports the first column of the matrix by default. To select a different column or row of the matrix, click Select Column or Row. This parameter is optional.
Data set name
— Data set name
text
Enter a name for the data set or accept the default name.
Manage data sets
— Manage previously imported data sets
list of data sets
Manage previously imported data sets. Click the data set of interest, then click the buttons below this pane to view the data (View), set the bin rules (Set Bin Rules), rename the data set (Rename), or delete the data set (Delete).
Data preview
— Preview plot of data
histogram plot
Display a preview plot of the variable selected from the Data drop-down menu.
Fit name
— Name of fit
text
Enter a name for the fit or accept the default name.
Data
— Data set to fit
list of data sets
Specify the data to fit by selecting a data set from the drop-down list.
Distribution
— Distribution to fit
Normal
(default) | Exponential
| Weibull
| Non-parametric
| ...
Specify the distribution to fit by selecting a distribution name from the drop-down list.
Exclusion rule
— Data exclusion rule
list of exclusion rules
Specify a rule to exclude some data values by selecting an exclusion rule from the drop-down list. To populate this drop-down list, you must first define exclusion rules by clicking Exclude in the main window of the app. This parameter is optional
Plot
— Flag to plot fitted distribution
checked (default) | unchecked
Specify which fit or fits to plot in the main window by selecting the Plot check box next to each fit. Clear the Plot check box to remove a fit from the plot.
Conf bounds
— Flag to plot confidence bounds
unchecked (default) | checked
If you select Plot for a particular fit, you can select Conf bounds to display the confidence bounds for that fit on the plot in the main window. Clearing the Conf bounds check box removes the confidence intervals from the plot. The Distribution Fitter app displays confidence bounds only if the Display Type in the main window is set to Cumulative probability (CDF), Quantile (inverse CDF), Survivor function, or Cumulative hazard.
Fit
— Fit to evaluate
list of fits
Select one or more fits from the list to evaluate.
Function
— Available functions to fit
Density (PDF)
(default) | Cumulative probability (CDF)
| Quantile (inverse CDF)
| Survivor function
| Cumulative hazard
| Hazard rate
Specify the type of probability function to evaluate from the drop-down list. Available probability functions include the probability density function (pdf), cumulative distribution function (cdf), quantile (inverse cdf), survival function, cumulative hazard, and hazard rate.
At x =
— Values at which to evaluate function
numeric vector
Specify a numeric vector of values at which to evaluate the function. If you specify Function as Quantile (inverse CDF), this field name changes to At p = and you enter a vector of probability values.
Compute confidence bounds
— Flag to compute confidence bounds
unchecked (default) | checked
Select Compute confidence bounds to compute the confidence bounds for the selected fit. This check box is enabled only if you specify Function as Cumulative probability (CDF), Quantile (inverse CDF), Survivor function, or Cumulative hazard. This parameter is optional.
Level
— Level for confidence bounds
95% (default) | numeric value
Specify the level at which to compute the confidence bounds. This check box is enabled only if you specify Function as Cumulative probability (CDF), Quantile (inverse CDF), Survivor function, or Cumulative hazard.
Plot function
— Flag to plot function
unchecked (default) | checked
Select Plot function to display a plot of the distribution function, evaluated at the points that you enter in the At x = field, in a new window. This parameter is optional.
Exclusion rule name
— Name of exclusion rule
text
Enter a name for the exclusion rule.
Exclude sections
— Define data exclusion rules numerically
numeric value
Specify lower and upper limits for the data numerically.
Exclude graphically
— Define data exclusion rules graphically
list of variables
Specify lower and upper limits for the data by selecting a variable from the Select data drop-down list and clicking Exclude Graphically. An interactive plot opens in a new window, where you can add lower or upper limits by clicking and dragging a boundary on the plot.
Existing exclusion rules
— List of existing exclusion rules
list of exclusion rules
Select an existing exclusion rule from the list. You can copy, view, rename, or delete exclusion rules by clicking the appropriate button.
Programmatic Use
distributionFitter
distributionFitter
opens the Distribution Fitter app, or
brings focus to the app if it is already open.
distributionFitter(y)
distributionFitter(y)
opens the Distribution Fitter app
populated with the data specified by the vector y
.
distributionFitter(y
,cens
)
y
,cens
)distributionFitter(
uses the vector y
,cens
)cens
to specify whether the observation
y(j)
is censored, (cens(j)==1)
, or
observed exactly, (cens(j)==0)
. If cens
is
omitted or empty, then no y
values are censored.
distributionFitter(y
,cens
,freq
)
y
,cens
,freq
)distributionFitter(
uses the vector y
,cens
,freq
)freq
to specify the frequency of each element
contained in y
. If freq
is omitted or
empty, then all values in y
have a frequency of 1.
distributionFitter(y
,cens
,freq
,dsname
)
y
,cens
,freq
,dsname
)distributionFitter(
creates a data set with the name y
,cens
,freq
,dsname
)dsname
using the data vector,
y
, censoring indicator, cens
, and
frequency vector, freq
. Specify dsname
as
a character vector or string scalar, for example,
'mydata'
.
Version History
Introduced before R2006aR2024a: Distribution Fitter app uses the MATLAB default color scheme
Starting in R2024a, the Distribution Fitter app uses the MATLAB default color scheme instead of static colors to determine the colors of graphics objects.
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