# Tagged Questions

For questions about distributions built-in in Mathematica, and functions that operate on them. Also includes questions about defining your own distributions.

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### How to generate two group of $n$ random numbers in $U(0,1)$ such that sum of these two groups equal? [on hold]

I want to have two groups of $n$ random numbers $u_i$ and $v_i$ in $U(0,1)$, such that $\sum u_i = \sum v_i$ What I tried is: I can firstly get $u_i$ by ...
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### Limit involving DiracDelta gives zero [closed]

Why is the following limit zero? In[147]:= Limit[DiracDelta[ϵ], ϵ -> 0] Out[147]= 0 It does not matter if the limit is taken from either sides (+/-), since ...
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### Linear fit with conditional noise distribution

I need to fit a linear model of the form $y_i = a · x_i + b + e_i$. The $e_i$ are independent noise from a distribution that depends on $x$ as well as on global parameters of the data; however, the ...
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### Gaps in CDF produced from HistogramDistribution

I have about 200 real numbers spread over the range 0-400. I use HistogramDistribution to bin them and PDF to create the ...
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### Working with $X^2$, where $X$ has the uniform distribution in $[-b,b]$

Consider $b>0$ and let $X \sim U[-b,b]$ (the continuous uniform distribution in $[-b,b]$ ). I want to do two computations in Mathematica. First is to compute the density function of $X^2$, which I ...
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### Mean of a half-Cauchy distribution

I am trying to calculate the mean (if it exists) of a half-Cauchy distribution. I know that the mean of the a Cauchy is undefined, but I was wondering whether the same is true of a half-Cauchy? (A ...
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### Fitting data to an Normal Inverse Gaussian distribution

I am using data which I suspect is distributed according to the Normal Inverse Gaussian distribution (NIG). The literature says that the 4 parameters of the NIG can be estimated from the sample mean, ...
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### How to evaluate if a list obeys the Normal distribution?

I am processing a data when I encountered this problem. I use the way of plotting the "normal probability plot" to show the result The list I have is: ...
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### Boundary parameter in Beta Distribution

I use EasyFit to find the probability distribution of my data. It turns out the data follows BetaDistribution with 0.54022,0.70601 shape parameters and 1.33,6.83 continuous boundary parameters I am ...
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### Exploring contours plots of two Binormal distributions

I am facing a little interesting problem. Let´s suppose two binormal distributions, as follows: ...
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### Non-existent PDF for combined MixtureDistribution and TransformedDistribution?

I am trying to mix two discrete distributions, one of them shifted by an integer amount by means of TransformedDistribution. When I then try to access the mix, it responds to CDF but not PDF. This ...
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### Finding Distribution based on quantile data

I am trying to determine an approximate distribution based on quantile data. I have the following information regarding Profit/Loss from an investing strategy backtest, and I want to use the data to ...
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### Proper command to fit a distribution with data incomplete in a known way

Here is my scenario: got some data that I have to fit to a specific parametric family of probability distributions (cannot be changed). Data consist of several bunches of integers between, say, 0 and ...
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### How to pass a custom method to a particular option?

In an answer to my question More efficient method to compute moments of the Johnson $S_B$ distribution, J. M. has come up with a method to compute the moments of the Johnson $S_B$ distribution, which ...
254 views

### More efficient method to compute moments of the Johnson $S_B$ distribution

Here is a very specific feature request. I need Mean[JohnsonDistribution["SB", γ, δ, 0, 1]] When I issue e.g. ...
107 views

### Scale SmoothHistogram curve to Histogram

Like in this question, I would like to display a histogram and a smooth histogram in the same plot. I believe the default “bin height specification” (or $\textit{hspec}$) for ...
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### Question about Mann-Whitney implementation in Mma

So, I've been doing some statistics using Mma. Typically, the Mann-Whitney U test is used to compare non-normally distributed samples, whose medians are compared if both distributions exhibit similar ...
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### Is there any function that compares distributions of two populations?

Imagine I have two populations that I want to test whether they exhibit similar shape distributions. Is there such a function that does this sort of testing already implemented? I am asking this ...
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### Plot a product of Beta distributions

I would like to plot the PDF of the product of a $Beta(1,1)$ and $Beta(3/2,1/2)$ random variables. I can use the following to calculate the PDF at a point $x$: ...
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Observe: ...
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### Possible bug in VonMisesDistribution?

Bug introduced in 10.2 or earlier and fixed in 10.3 Observe: ...
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### How to define a bivariate skew normal distribution?

There is BinormalDistribution that handles easily bivariate normal distribution and its mixtures. There is also ...
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### Mixture of a bivariate distribution defined as a copula

I define a bivariate distribution: ...
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### Error message when exporting plot as XLS file

I imported data from excel which has 300 data (which are change in CDS spread). I want to compute corresponding CDF for the data using kernel density estimation. I get the CDF plot but cannt get the ...