Questions on the statistical functions of Mathematica.

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0
votes
0answers
514 views

histogram fit for probability density

I am trying to fit the (probability density) histogram of some data with the exponential function, but I am having difficulties. My raw data are in file called ...
0
votes
1answer
173 views

Custom BoxWhisker Plot

I’d like to figure out how I can show my entire dataset overlaid on a box whisker plot. ...
1
vote
2answers
181 views

Discretizing data using quantiles in Mathematica

I am trying to discretize a long array of real numbers into a uniformly distributed integer array. To do this I am identifying the quantile where each real value sits and writing it out to the output ...
6
votes
1answer
213 views

Better way to get Fisher Exact?

I want to perform a Pearson's $\chi^2$ test to analyse contingency tables; but because I have small numbers, it is recommended to perform instead what is called a Fisher's Exact Test. This requires ...
3
votes
0answers
214 views

Sparse Principal Component Analysis

I'd like to run sparse PCA on some economic data. There appear to be several R functions available including elasticnet and PMA but I wanted to check if anyone had something coded up directly in MMA ...
5
votes
2answers
134 views

Best way to represent a joint distribution

The motivation for this question is producing a distribution that produces the gender and age of an individual when the distribution of ages depends on gender. Suppose I want a distribution which, ...
0
votes
0answers
261 views

Non linear model fit mathematica

I want to fit experimental data (temp,alpha) to the following equation for calculating k and Ea -Log[alpha]^n = function(k,Ea,temp) However i do not know ...
2
votes
2answers
122 views

Why I need Evaluate for the Plot of the probability density function of PolyaAeppliDistribution?

I encountered this when I was trying to answer this question. I just can't understand why the following code will only give a line at $y=0$: ...
1
vote
2answers
320 views

Calculating the Mean of a Truncated Multinormal Distribution

First, I'm a little disappointed that Mathematica balks at: Mean[TruncatedDistribution[{{0, Infinity}},MultinormalDistribution[{0}, {{1}}]]] Second, is the ...
1
vote
1answer
165 views

How can I show a rotated PDF plot superimposed on a ListPlot of the underlying data?

I have a set of 3 lifetime datasets in lists called values1, values2 and values3. values1 = {53377., 16542., 31418., 5629., 17654., 7365., 15797., 862., 76906., 10073.}; values2 = {74412., 15620., ...
-1
votes
2answers
313 views

Fitting a beta distribution to a probability density curve

If I have a spectral data set showing measured energy on the y-axis and frequency on the x-axis, how would I go about fitting this to a beta distribution? For example, lets say I had the data for the ...
3
votes
1answer
120 views

Expectation problem using empirical distribution

I am having trouble with this Mathematica command: ...
2
votes
5answers
551 views

Generating a list of integers that roughly satisfy a distribution

Say I have a normal distribution, NormalDistribution[25, 7] I'd like integers from 1 to 50, not sampled at random from that distribution, but sampled in a way ...
11
votes
2answers
219 views

Probability of the sum of the largest n samples

15 numbers are randomly chosen from U(0,1), what is the probability that the sum of largest four numbers is greater than 3.5? ...
4
votes
1answer
171 views

How to get an equivalent of WeightedData in Mathematica 8?

Is there an equivalent command of WeightedData (new in version 9) in Mathematica 8 or I have to define it by myself? I haven't found anything in the site or ...
4
votes
1answer
968 views

How does Mathematica estimate error on fit parameters?

When performing a fit using NonlinearModelFit (or any of Mathematica fitting functions, but I am particularly interested in nonlinear models), Mathematica makes a ...
2
votes
1answer
195 views

Judging the quality of fitting an EventData object to a distribution using LogRankTest

I have $389$ data points defined in an EventData object and want to judge the quality of fit of this data to a fitted $3$-parameter Weibull distribution. This ...
7
votes
2answers
495 views

BoxWhiskerChart with logarithmic axes

I would like to make a following chart Ideally I would also like to control the boxes position on a logarithmic x-axis. Some inspiration how to do the latter may be found in the answer to my ...
3
votes
0answers
123 views

Where can I find the Distributions Palette?

I was watching the "Statistics: Modeling with Statistical Distribution" Training Course http://www.wolfram.com/training/videos/DAT016/ and in one of the slides, the following image showed up. Does ...
5
votes
0answers
543 views

What exactly is “ParameterErrors” of NonlinearModelFit?

I am trying to get what I call a "$\chi^2$ fit". This means taking a function $f(x,p)$ of the variable $x$ with a parameter $p$ and finding the value of $p$ that minimizes the "distance" from a data ...
0
votes
1answer
177 views

plot an exponential statistical function

I have this exponential function, where j is unknown. How can I plot the variance function for $k= 0.1, \; 1, \;10$ $$f_{j,k}(y)=\frac{\sqrt{j}}{\sqrt{2 \pi}}e^{\sqrt{jk}}y^{-\frac{1}{2}} ...
9
votes
1answer
665 views

How does Mma compute Confidence Intervals?

I am trying to understand how Mma computes the Confidence Intervals after a NonlinearModelFit. Consider the following example: ...
1
vote
1answer
332 views

How do I select a random sample without replacement? [closed]

What is the module that selects a random sample of size k (without replacement) from a given population of size n, involving the command Subsets.
3
votes
1answer
151 views

I need a technique for determining and drawing a line where the density in a listplot jumps up suddenly

Basically I have a two dimensional list plot with a bunch of points between the square of (0,0) and (1,1). The y-values of these points are drawn from a uniform probability distribution between 0 and ...
0
votes
3answers
547 views

Plotting confidence intervals

The documentation for PDF has an example for plotting a confidence interval of a standard normal distribution: ...
2
votes
2answers
53 views

Evaluating a SmoothKernelDistribution at a point

I would like to evaluate the value of the following SmoothKernelDistribution at the location, say, 2.35. What is the right way to do it? ...
5
votes
1answer
167 views

Reverse engineer a sample value from a CDF

The image below shows the cumulative distribution of a normal distribution with mean = 4 and standard deviation = 1. Notice that if you have a value with a rank of 0.8 (meaning it would be 80th item ...
3
votes
1answer
217 views

How could I improve this Central Limit Theorem demonstration speed- and content-wise?

My purpose is to demonstrate the Central Limit theorem by assuming two custom distributions, taking some random samples, calculating their means and ploting the results. Ideally, the histograms should ...
11
votes
3answers
248 views

How to efficiently find moments of a multinormal distribution?

I have a multinormal distribution with covariance matrix $\sigma$ and zero mean. I want to find moment $$ E[x_1^{r_1}x_2^{r_2}\cdots x_n^{r_n}] =\,? $$ Of course, there is a build-in function ...
0
votes
1answer
141 views

Understanding distribution chart

How to explain DistributionChart function in mathematica, For example: if I have ...
6
votes
2answers
1k views

How can I compute and plot the 95% confidence bands for a fitted logistic regression model?

I have a set of binary data that I' d like to fit a logistic regression model to and show the 95% confidence band around the fitted function. I can produce the regression model but how do I compute ...
0
votes
0answers
157 views

Discrete distribution binomial set up

I hope one of you guys can help me out. I am trying to visualize a discrete distribution based on a binomial distribution and a mixed binomial distribution. In the first step I started to determine ...
5
votes
1answer
144 views

PearsonChiSquareTest: set degrees of freedom

How to set degrees of freedom for PearsonChiSquareTest? I have this: ...
0
votes
1answer
113 views

Distance to a MultivariateStatistics median

I have a population of objects (each of which is described by a list of about a half-dozen real numbers), and I'd like to find some reasonable kind of distance between each of several different test ...
4
votes
1answer
212 views

Defining five-parameter Pearson distribution by moments

How do you derive (or where can I find a derivation of) the equations to match the five parameters of a general Pearson distribution to a mean, variance, skewness, kurtosis, and condition that the ...
4
votes
3answers
642 views

Log-log scale smooth histogram

How can I create a smooth histogram with a log-log scale? I can use Histogram[data, "Log", "LogCount"] to get a log-log histogram, or I can use ...
4
votes
1answer
180 views

How to Use ProbabilityScalePlot with Censored Data?

I am trying to reproduce a ProbabilityScalePlot of censored data shown here (see Sample Analysis Plot). Here is my Mathematica code. First I deal with the uncensored case. ...
6
votes
1answer
657 views

How do I calculate Standard Deviation confidence intervals in Mathematica?

I have a series of simulation results and I would like to demonstrate how the confidence interval for the mean and standard deviation decrease as the number of results increases. I have done this for ...
3
votes
1answer
217 views

DistributionFitTest with WeightedData?

My problem is related to statistical testing with weighted data. I have a data sample and I assume that a part of the data follows a specific distribution (Pareto). So I fit my data to a distribution ...
5
votes
1answer
975 views

Hodrick–Prescott filter (one-sided version)

I am interested in implementing Hodrick–Prescott filter (HP filter) on my time series data in Mathematica. I know that there is already a version of two-sided original filter for Mathematica (see ...
3
votes
4answers
230 views

Descriptive statistics of two events

I am trying to use the descriptive statistics feature of Mathematica to answer the following question: suppose I have two events, A and B, whose occurrence is described by a normal distribution around ...
4
votes
1answer
440 views

Using DistributionFitTest on custom distributions in Mathematica 8

I originally posted this question on Stack Overflow, but I didn't get any answers, and I'm hoping to have better luck here. I'm trying to compute the goodness-of-fit of a bi-modal Gaussian ...
2
votes
1answer
130 views

Confidence level for Binomial

For 617519 first time births there were 317528 boys. Give an estimate with 99% confidence interval for the probability that the first time birth is a boy. I have searched for the confidence ...
1
vote
1answer
142 views

Value for x such that |(x-y)| is minimum

I have a list Y={y1,y2,y3,...,yn} And I would need to find x such that Abs[x-Y[[i]]] for all $y_i$ in $Y$ is minimum. ...
6
votes
3answers
539 views

Calculate probability function

I would like to calculate the following with Mathematica: Let $X$ be a random variable with probability function $$p(x)= \left\{ \begin{matrix} \frac{x}{6} & \text{for }x \in \{1,2,3\}\\ 0 ...
13
votes
1answer
328 views

Randomness test suites that can be invoked from Mathematica

There are several test suites referenced at csrc.nist.gov designed to test a (pseudo-)random byte sequence for randomness, and discover possible skews, correlations, patterns, or other hidden ...
4
votes
2answers
421 views

How to make a conditioning plot?

I'd like to make a conditioning plot just like coplot in R. Is there a pre-made solution or do I have to make a bunch of plots individually? Edit: This is an example from r screenshots. It is a way ...
1
vote
0answers
973 views

How to Output Chi-Squared Statistics when using NonLinearModelFit

I am using NonLinearModelFit for some curve fitting and I was wondering if NLM is able to output chi-squared/leastsquared statistics from the best-fit parameters and confidence intervals. From my ...
1
vote
1answer
161 views

plot probability

Hi I just want to flatten a function, I tied it with Joined->True, but it did not work, hope somebody of you can help me. This is my code: ...
2
votes
1answer
337 views

Problem with Covariance Matrix Output in NonlinearModelFit

I am running NonlinearModelFit based off of some simulated data and trying to fit to a function with more than one parameter. Eventually, I would like to fit to 5 ...