Community Profile # Richard Willey

### MathWorks

Active since 2011

#### Statistics

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Crossvalidation of Classification Trees?
I recommend that you look at the following example from the file exchange http://www.mathworks.com/matlabcentral/fileexchange...

mer än 9 år ago | 0

linear regression
Alternatively, if you have the 12a version of Statistics Tbx X = [1,2,3,4,5,6,7,8,9]; Y = [4 5 6 9 8 7 4 1 2]; my...

mer än 9 år ago | 1

How to apply Random walks ?
MATLAB includes a wide variety of functions that can be used to simulate a random walk. Depending on what precisely you want to...

mer än 9 år ago | 1

What is a reasonable lower time limit for regstats?
MATLAB and Statistics Toolbox provide a variety of ways to perform a regression. For example, if I am performing a simple linea...

mer än 9 år ago | 1

Parametric bootstraping in curve fitting
In general when I hear the expression parametric bootstrap I think "parametric residual bootstrap" I'm attaching some simple ...

mer än 9 år ago | 1

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How do I Regression Fit a SinWave to a dataset?
Here's some simple code that illustrates how to perform nonlinear regression using the 12a release of Statistics Toolbox. Not...

mer än 9 år ago | 1

Homework help.
Couple quick questions / comments 1. are you sure you typed in the model correctly? This looks very close to a Gompertz fun...

mer än 9 år ago | 0

Curve fitting f(x,y) result
I'm attaching code that shows a couple different ways to solve your problem. I prefer the second option. The R^2 is slightly...

mer än 9 år ago | 1

Curve fitting f(x,y) result
Hi ZazOufUMl A "Poly31" model is different than the one that I suggested. (Poly31 will contain a number of cross terms). ...

mer än 9 år ago | 0

Curve fitting f(x,y) result
Hi there The "Poly54" fit type is specifying a 5th order polynomial in one direction and a 4th order polynomial in the other....

mer än 9 år ago | 0

Matlab - How to Generate Random Numbers from a Specific Probability Density
If Pv and Pa can both be described as functions of a, you might be able to use a univariate generator to generate plausible valu...

mer än 9 år ago | 0

Multicolinearity/Regression/PCA and choice of optimal model (2nd try)
I'm attaching some code that might provide helpful I also have a two part blog posting on this same subject that provides a b...

mer än 9 år ago | 0

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The problem of using rng to generate random numbers.
From the sounds of things, the simplest thing to do would be to generate all of your random numbers OUTSIDE your loop. Start ...

mer än 9 år ago | 0

The problem of using rng to generate random numbers.
It's hard to make a specific recommendation without known more about the use case. What (specifically) are you trying to acco...

mer än 9 år ago | 0

classifier
I did a webinar a couple years titled: "Computational Statistics: An Introduction to Classification with MATLAB". You can ...

mer än 9 år ago | 0

Surface Fitting Tool Coefficient Structure
Local regression (aka LOWESS/LOESS) and interpolation don't lend themselves to parametric representations. There really isn't a...

mer än 9 år ago | 0

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Curve smoothing using Matlab
I have a function called FitIt on the file exchange that might prove useful. FitIt combines Local regression (to smooth yo...

mer än 9 år ago | 0

Get Y values from Curve Fitting Tool
For simplicity, this code is using a simple linear model. However, the same syntax with work for your nonlinear regression. ...

mer än 9 år ago | 7

| accepted

Least squares linear regression when squares have to do with elasticity?
Here's a simple example using the new regression functions in the 12a release. All you need to do is pass the appropriate weigh...

mer än 9 år ago | 1

Multi-parametric fit with matlab
Hi Miguel fitensemble is able to handle multiple independent variables. You should be able to use this with the data set tha...

mer än 9 år ago | 0

| accepted

Multi-parametric fit with matlab
Hi Miguel From the sounds of things, your central problem is that you're unable to specify an equation that describes the rel...

mer än 9 år ago | 0

Classifiers. How can i draw 3-D plot ?
I have a webinar entitled An Introduction to Classification with MATLAB. The code is available for download from the file exc...

mer än 9 år ago | 0

How to merge two similar functions into a same function? any mathematical modeling method or tool box?
Hi Qian Implicitly, you seem to be suggesting that there is a single model that describes both of these sets of data. Rather...

mer än 9 år ago | 0

Classifiers. How can i draw 3-D plot ?
The SVM implementation in Bioinformatics Toolbox is limited to binary classification. The Naive Bayes classifier in Statistic...

mer än 9 år ago | 1

How to obtain Std of Coefficients from Curve Fitting
Hi George Conveniently, 12a also has a function call NonLinearModel %% Generate some data X = 2* pi*rand(100,1); ...

mer än 9 år ago | 0

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How to obtain Std of Coefficients from Curve Fitting
The 12a release of Statistics Toolbox has some very nice new capabilities for regression analysis. %% Generate some data ...

mer än 9 år ago | 0

how do I determine the probability distribution of data?
Sorry if this sounds like a silly question: Is there an absolute requirement that you describe your data using a parametric d...

mer än 9 år ago | 0

How to get regression statistics for several run with different data sets?
Hey there The following code assumes that you have the 12a release of Statistics Toolbox. (In other words, I am using the ne...

mer än 9 år ago | 0