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# Jeff Miller

309 total contributions since 2013

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Efficient code for obtaining the probability of X or less, when the PDF is known, but the CDF cannot be expressed precisely
Unless you have closed form or a good approximation to the CDF, it seems like your only option is to integrate the PDF with MATL...

1 day ago | 0

Compare Betas from two different GLMS
You might compare confidence intervals. For example, the estimated value for evidence control is .62033. Compute an approximate...

1 day ago | 0

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How can I simulate data from two different distribution using Copulas?
OK, then I think you are almost there. You have the data X, Y, and rhoXY. Start by estimating the parameters for your gamma an...

2 days ago | 0

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How can I simulate data from two different distribution using Copulas?
The question is a little confusing because the U values are from 0 to 1 but the Q values aren't. Q(1,:) looks like a gamma but ...

3 days ago | 0

seed for Monte Carlo
It sounds like you would be better off not to set the seed at all--just use MATLAB's default seed, which is different every time...

4 days ago | 0

Running repeated anova on all elements of large matrix
If you really just want the F value, you can probably get it much faster by looking up the formulas for the one-factor within-Ss...

4 days ago | 0

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Generate column of random numbers that change slowly from row to row
You might generate the random points as you have but then smooth them with the smooth or filter function, e.g., sprob = zeros(s...

6 days ago | 0

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What the two columns represnt when i generate a multivarite normal random numbers
The two columns represent the two variables measured for each case, and the N rows represent the N randomly selected cases from ...

7 days ago | 0

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Fitting a non-linear model to my data
Take logs and use multiple regression. That is, fit the model log(y) = a log(x1) + b log(x2) etc This will give you the best ...

7 days ago | 1

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Integrating a t-test into a function how-to
Put in a breakpoint at the ttest2 line and check the inputs x and y that you are passing. These must not be what ttest2 expects...

10 days ago | 0

Fit Gaussian mixture model with weighted observations
It's not exactly clear (to me either) what it means to weight the different observations in this context, but maybe you have som...

12 days ago | 0

Convolution of two different pdf (uniform and normal distribution)
The Cupid toolbox will do this. For example, u = Uniform(0,100); n = Normal(100,10); % 2nd parameter is sigma, not sigma^2 c...

16 days ago | 0

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Within- & between-subjects in 'anovan'
I also found the lack of between/within terminology a bit daunting. With respect to your first question, here is an example tha...

21 days ago | 1

Question

any trick to stop fminsearch early?
I am using fminsearch to minimize an error score in fitting a model to many, many data sets. Often, the error score gets close ...

22 days ago | 2 answers | 0

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How can I introduce a known autocovariance to a lognormal process
You should be able to do it by generating your sequence one element at a time, if you can't find a canned routine that will do i...

25 days ago | 0

How to calculate the conditional proabability?

1 month ago | 0

How to find the maximum of a normalized fit of a histogram
Try this: dist = Histogram(2) maxnorm = max(dist.YData); line([min(dist.XData) max(dist.XData)], [maxnorm maxnorm], 'LineWidt...

1 month ago | 0

Extreme Value Distribution y-axis not same with Histogram
histogram(total,'normalization','pdf');

1 month ago | 0

Multiple univariate or multivariate analysis?
No, that's probably not the right way to go. The problem with this approach is that you have a 5% chance of making a type 1 err...

1 month ago | 0

How to calculate the P-value using chi-square and degrees of freedom
p = 1 - chi2cdf(x,df)

1 month ago | 0

Is there a way to do a multi normal distribution fitting in Matlab?
The sigma isn't really off. GMModel.Sigma is variance = sigma^2

1 month ago | 0

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Log-Normal fit of histogram
fitdist wants the x values that were tabulated to get the histogram, not the bin counts. From your histogram, it looks like you...

1 month ago | 0

Parameter estimation - estimate integers only
One way to do this is to write your objective function to return an error function that is linearly interpolated between two int...

1 month ago | 0

Fmincon: how to change input variable of function which is not a design variable?
If I follow what you are trying to do, one way is by nesting your objective function within some outer master function, somethin...

1 month ago | 0

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How to define the Conditional probability density function from a n-by-2 matrix ?
Maybe start with 'ksdensity' to estimate the joint pdf of x & y from your observed x,y pairs. Once you have a good numerical es...

2 months ago | 0

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Plotting average of many empirical cumulative distribution functions
I'm pretty sure there is no function to do that. To compute the average function by Vincentizing, you first choose a set of CDF ...

2 months ago | 0

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Problems with fmincon for design optimization
Hi Soheil, You have posted a lot of information and I certainly have not digested even a large fraction of it (it would take me...

2 months ago | 0

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CDF-vector- 2 random variables
You apparently have a probability for each of the x and y values. So, you can just compute the different possible Ln(Z) values f...

2 months ago | 0

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