Questions on the statistical functions of Mathematica.

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6
votes
2answers
106 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, ...
1
vote
0answers
161 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
97 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
264 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
121 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
180 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
90 views

Expectation problem using empirical distribution

I am having trouble with this Mathematica command: ...
2
votes
5answers
252 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 ...
1
vote
1answer
188 views

build and estimate a time series process

I want to generate an EGARCH process. My problem is that I do not see how to create new processes beyond those available. The process itself is : $$\epsilon(t) = \sigma(t) \eta(t)$$ ...
10
votes
2answers
198 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? ...
3
votes
2answers
95 views

Expected sum of largest 3

I pick 4 numbers from the Uniform Distribution. I need the expected value of the sum of the 3 largest. I am pretty sure that the answer is 9 / 5 which agrees with a simulation. I would like to get ...
4
votes
1answer
106 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
389 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
158 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 ...
6
votes
2answers
340 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 ...
2
votes
0answers
99 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 ...
2
votes
0answers
190 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
163 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}} ...
7
votes
1answer
320 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: ...
0
votes
1answer
184 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
121 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
312 views

Plotting confidence intervals

The documentation for PDF has an example for plotting a confidence interval of a standard normal distribution: ...
3
votes
1answer
131 views

Calculate the covariance of a large matrix

I have to compute the covariance of 50 very large integer matrices (2500x2000 elements). However, according to my estimation this will take around 10 days. Do you have any ideas how to speed things ...
2
votes
2answers
42 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
146 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
142 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
187 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
114 views

Understanding distribution chart

How to explain DistributionChart function in mathematica, For example: if I have ...
-3
votes
3answers
176 views

Statistical analysis of a data file and its Plot [closed]

As the title says, I have an external data file which contains thousands lines of data. The data file contains eight columns and here is what I would like to plot: Let's assume that the length of the ...
6
votes
2answers
795 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
123 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
109 views

PearsonChiSquareTest: set degrees of freedom

How to set degrees of freedom for PearsonChiSquareTest? I have this: ...
0
votes
1answer
107 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
157 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 ...
3
votes
3answers
347 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 ...
3
votes
1answer
119 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
479 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
157 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
562 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 ...
1
vote
1answer
194 views

SinglePredictionBands versus MeanPredictionBands from NonlinearModelFit

From my Statistics lectures I know the term confidence and prediction interval, whereas the confidence interval is smaller than the prediction interval. If I plot the mean and single prediction bands ...
3
votes
4answers
214 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
348 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
93 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
128 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
417 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 ...
12
votes
1answer
218 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
311 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 ...
0
votes
0answers
518 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 ...
0
votes
1answer
138 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
228 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 ...