std
Standard deviation of probability distribution
Syntax
Description
Examples
Standard Deviation of a Fitted Distribution
Load the sample data. Create a vector containing the first column of students' exam grade data.
load examgrades
x = grades(:,1);
Fit a normal distribution object to the data.
pd = fitdist(x,'Normal')
pd = NormalDistribution Normal distribution mu = 75.0083 [73.4321, 76.5846] sigma = 8.7202 [7.7391, 9.98843]
Compute the standard deviation of the fitted distribution.
s = std(pd)
s = 8.7202
For a normal distribution, the standard deviation is equal to the parameter sigma
.
Standard Deviation of Skewed Distribution
Create a Weibull probability distribution object.
pd = makedist('Weibull','A',5,'B',2)
pd = WeibullDistribution Weibull distribution A = 5 B = 2
Compute the standard deviation of the distribution.
s = std(pd)
s = 2.3163
Standard Deviation of Triangular Distribution
Create a triangular distribution object.
pd = makedist('Triangular','A',-3,'B',1,'C',3)
pd = TriangularDistribution A = -3, B = 1, C = 3
Compute the standard deviation of the distribution.
s = std(pd)
s = 1.2472
Standard Deviation of a Kernel Distribution
Load the sample data. Create a vector containing the first column of students’ exam grade data.
load examgrades;
x = grades(:,1);
Create a probability distribution object by fitting a kernel distribution to the data.
pd = fitdist(x,'Kernel')
pd = KernelDistribution Kernel = normal Bandwidth = 3.61677 Support = unbounded
Compute the standard deviation of the fitted distribution.
s = std(pd)
s = 9.4069
Input Arguments
pd
— Probability distribution
probability distribution object
Probability distribution, specified as one of the probability distribution objects in the following table.
Distribution Object | Function or App Used to Create Probability Distribution Object |
---|---|
BetaDistribution | makedist , fitdist , Distribution Fitter |
BinomialDistribution | makedist , fitdist ,
Distribution Fitter |
BirnbaumSaundersDistribution | makedist , fitdist ,
Distribution Fitter |
BurrDistribution | makedist , fitdist ,
Distribution Fitter |
ExponentialDistribution | makedist , fitdist ,
Distribution Fitter |
ExtremeValueDistribution | makedist , fitdist ,
Distribution Fitter |
GammaDistribution | makedist , fitdist ,
Distribution Fitter |
GeneralizedExtremeValueDistribution | makedist , fitdist ,
Distribution Fitter |
GeneralizedParetoDistribution | makedist , fitdist ,
Distribution Fitter |
HalfNormalDistribution | makedist , fitdist ,
Distribution Fitter |
InverseGaussianDistribution | makedist , fitdist ,
Distribution Fitter |
KernelDistribution | fitdist , Distribution Fitter |
LogisticDistribution | makedist , fitdist ,
Distribution Fitter |
LoglogisticDistribution | makedist , fitdist ,
Distribution Fitter |
LognormalDistribution | makedist , fitdist ,
Distribution Fitter |
LoguniformDistribution | makedist |
MultinomialDistribution | makedist |
NakagamiDistribution | makedist , fitdist ,
Distribution Fitter |
NegativeBinomialDistribution | makedist , fitdist ,
Distribution Fitter |
NormalDistribution | makedist , fitdist ,
Distribution Fitter |
PiecewiseLinearDistribution | makedist |
PoissonDistribution | makedist , fitdist ,
Distribution Fitter |
RayleighDistribution | makedist , fitdist ,
Distribution Fitter |
RicianDistribution | makedist , fitdist ,
Distribution Fitter |
StableDistribution | makedist , fitdist ,
Distribution Fitter |
tLocationScaleDistribution | makedist , fitdist ,
Distribution Fitter |
TriangularDistribution | makedist |
UniformDistribution | makedist |
WeibullDistribution | makedist , fitdist ,
Distribution Fitter |
Output Arguments
s
— Standard deviation
nonnegative scalar value
Standard deviation of the probability distribution, returned as a nonnegative scalar value.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
The input argument
pd
can be a fitted probability distribution object for beta, exponential, extreme value, lognormal, normal, and Weibull distributions. Createpd
by fitting a probability distribution to sample data from thefitdist
function. For an example, see Code Generation for Probability Distribution Objects.
For more information on code generation, see Introduction to Code Generation and General Code Generation Workflow.
GPU Arrays
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
Version History
Introduced in R2013a
See Also
var
| mean
| makedist
| fitdist
| Distribution Fitter
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