Questions tagged [distribution-identification]
Questions about recognizing a probability distribution from a figure, formula, or text description. Please use a specific, informative title.
71
questions
2
votes
2answers
47 views
Fitting a distribution like exponential but with always negative $\frac{d^2}{dx^2} \log \text{pdf}(x)$
I have some continuous data in the domain $[0,\infty]$ which I have physical reason to believe is almost, but not quite exponentially distributed. The difference between my idea of a distribution and ...
1
vote
1answer
23 views
What is the name and formalism of this discrete distribution? [closed]
I am searching the name of something similar to a binomial distribution, but with individual probabilities (P(1) to P(N)).
I calculated (brute-forced with a script) the probability of k positive ...
0
votes
1answer
53 views
What distribution is $P_X(x \mid K, N) = \frac{1}{ ( 1 + N)^K} {x + K -1 \choose x} \left( \frac{N}{1+N}\right)^x$?
What kind of distribution is the following:
$$
P_X(x \mid K, N) = \frac{1}{ ( 1 + N)^K} {x + K -1 \choose x} \left( \frac{N}{1+N}\right)^x
$$
and how can I find $P_X(x < x_0 \mid K, N)$?
3
votes
0answers
133 views
What distribution has the p.d.f. of form $\frac{e^{-b \cdot x} \cdot x^c}{1 + e^{-k \cdot (x+a)}}$ for $x >0$ and parameters $b > 0, k > 0, c > 0$?
In my work I met the p.d.f. of form $$p(x) \propto \frac{e^{-b \cdot x} \cdot x^c}{1 + e^{-k \cdot (x+a)}}$$ with support $x \in [0, +\infty)$ and positive parameters $b > 0, k > 0, c > 0$.
...
0
votes
0answers
36 views
Does anyone recognize this probability distribution?
Can someone tell me what distribution/ family of distributions is this?
0
votes
0answers
36 views
How to choose and plot the most appropriate distribution in R?
I need to choose the distribution that best fits my data for different datasets.
There are similar discussions here and here, but I am still struggling to find proper solution.
My first attempt was ...
1
vote
1answer
42 views
Let $f_X(x)= \frac{x^2e^{-\frac{x^2}{2}}}{\sqrt{2\pi} } 1_{(-\infty,+\infty)}$, what is this distribution called?
Let $$f_X(x)= \frac{x^2e^{-\frac{x^2}{2}}}{\sqrt{2\pi} } 1_{(-\infty,+\infty)},$$
is the pdf of random variable $X$. What is this distribution called?
I only know $f_X(x)\propto x^2e^{-\frac{x^2}{2}} ...
0
votes
0answers
20 views
Help selecting a correct distribution for this data
I'm a geologist working with some sparse borehole data. The boreholes sample igneous intrusions and we're trying to fit a distribution to the thickness of the intrustion vs frequency (for use in other ...
1
vote
0answers
31 views
What probability distribution would be look like this?
I was playing with R, I started with adding consecutive binomials (the n parameter of the second binomial variable depends of the result of the first binomial and so on...). After a few more ...
0
votes
1answer
37 views
Help finding the type of distribution
I am doing a question which involves the following probability density function
$$f(x;\mu,\lambda) = \sqrt{\frac{\lambda}{2\pi x^{3}}} exp\bigg(\frac{-\lambda(x-\mu)^2}{2\mu^2x}\bigg), x>0, \lambda,...
0
votes
0answers
35 views
What distribution could the data stem from?
From checking the histogram of the distribution I had the intuition that the data could follow a Poisson or an exponential distribtuion.
However, Lilliefors test that the data is exponentially ...
3
votes
2answers
78 views
Estimating the blockchain mining time for $N$ nodes
I am trying to simulate a set of times for the below problem.
There are N nodes. Each node generates a random number($R$) in the range $[0,K]$ per second. Guess the time it takes by each node to ...
0
votes
0answers
22 views
Test for statistical distribution
I'm new to statistical analysis and I'm trying to identify which distribution fits my BD better. My BD has length of stay (LOS) data in two different hospitals: ...
11
votes
2answers
719 views
What kind of distribution does this have?
Currently I'm trying to figure out the distribution of the following:
$X \sim \frac{\sqrt{n}}{\sqrt{Gamma(n,\beta)}}$ where the denominator follows a $Gamma(n,\beta)$ distribution.
I've checked out ...
1
vote
1answer
17 views
calculate mean of normal distribution given SD and probability corresponding to a single range
Suppose that I have a normally distributed variable with unknown mean and known SD: $X \sim N(\mu, 1)$. I also know that $P(-2 < X < 2) = 0.3.$ Is it possible to calculate $\mu$ from this ...
0
votes
0answers
65 views
Is there a way to find a statistical distribution for the below data?
Is there a way to find a statistical distribution for the below data?
This is derived from frequency count of different topics in a large corpus of news stories. I wonder if this follows a Poisson ...
2
votes
0answers
28 views
What's the name for a distribution where at the extreme there are more values farther away from the mean than closer?
The image below from this blog provides a good example. I'm talking about distributions that are roughly Gaussian except that there are more values at the high end that would be expected. In ...
0
votes
0answers
58 views
QQ plot distribution check
I want to check if a distribution is log normal or not by using qq plot. So for convenience I am creating a
lognormal distribution using stats and checking it in ...
0
votes
0answers
41 views
Are there any methods to test whether a data set obeys a certain probability distribution?
If one has a set of data, are there any methods or techniques of testing whether that set obeys a candidate distribution?
I have thought of a number of possibilities:
Simply histogram and look at it, ...
0
votes
0answers
29 views
How can I identify an unfamiliar cumulative distribution function?
I have 116 Bessel-corrected sample variances (average of squared distances from sample mean), each from a sample of three measurements. All measurements were done using the same method.
I had ...
4
votes
1answer
71 views
What is the name of this distribution?
I came across this: a categorical distribution with $K=10,000$ parameters (categories), and we take only few samples from this distribution, say $N=400$ (the point is $N < K$). Now, obviously, not ...
0
votes
0answers
65 views
How can i find a suitable distribution that fits my data?
I have some data on prevalence of a given infection, provided for each country for 6 different age groups. I am trying to find a suitable distribution that may be suitable to model capture the ...
0
votes
1answer
318 views
Compare distribution to given shapes to find the most similar
I have a multiple comparison problem between some thousands of correlation distributions and given shapes.
I have computed pair-wise correlation for a given set of gene expresion data, and I have ...
12
votes
1answer
223 views
Name for a distribution between exponential and gamma?
The density $$f(s)\propto \frac{s}{s+\alpha}e^{-s},\quad s > 0$$ where $\alpha \ge 0$ is a parameter, lives between the exponential ($\alpha=0$) and $\Gamma(2,1)$ ($\alpha \to \infty$) ...
2
votes
1answer
88 views
Identifying a distribution
I am trying to understand what sort of distribution is produced by the following code.
Using the following Matlab code we can generate a distribution (normalized such that the sum of the set is equal ...
6
votes
2answers
271 views
Can anyone suggest a distribution for this histogram
I have some data and I am trying to identify its distribution. The nearest I can get is a skewed-Gaussian distribution, but I don't think it is. The data itself consists of 130000 points and is binned ...
3
votes
1answer
139 views
Name this distribution!
While looking for a link function for my model I realized I cannot find a good fit for the distribution of my Y (see fig. below).
It is the distribution of number of offspring for a given season, the ...
6
votes
2answers
6k views
Understanding the Cullen and Frey plot
I would like to figure out which distribution fits my data best.
Here is the histogram of my data :
I used the fitdistrplus package in R to try to find the best ...
3
votes
2answers
310 views
What does the distribution of bootstrapped values in this Cullen and Frey Graph tell me?
I am trying to find a suitable distribution to describe my data, and as one of the first few steps I created a Cullen and Frey Graph using the descdist command from ...
0
votes
0answers
50 views
To what distribution it's similar? Looks like an exponential but it's not
To what distribution it's similar? Looks like an exponential but it's not.
It's seems to have a property, that if I zoom it (xlim) then each time it has the same ...
2
votes
1answer
73 views
$X_i + X_i^2$ where $X_i \sim$ normal; what is the distribution?
$X_i + X_i^2$ where $X_i \sim$ normal. Does this sum have any particular distribution?
1
vote
0answers
22 views
Identifying the best fitting distribution type to test
Hi I tried to analyze a dataset, of USDT concurrency and following is the frequency distribution I received for log return
I need this dataset to fit for a particular distribution. Can we suggest ...
1
vote
3answers
843 views
How to determine which distribution fits my data set?
I have this data set which I am trying to find which distribution my data set can be accurately represented by using r. I performed the Shapiro-Wilk test and found that my data does not come from a ...
1
vote
0answers
41 views
Identifying the distribution of this data
I'm working with a datetime series, and each observation is the count of occurrences per that period. This sounds to me like these values would be Poisson distributed. But my EDA has left me ...
2
votes
3answers
116 views
How long is a distribution considered normal?
I have a dataset of metric distances ($n=5800$) and plotted those as a histogram. My initial thought was that this distribution looks normal. But after performing a Shapiro Wilk test and plotting the ...
3
votes
1answer
442 views
Is there a common underdispersed discrete distribution with unbounded support for general mean and variance?
I have a mean $\mu$ and a variance $\sigma^2$ with underdispersion, i.e., $\sigma^2<\mu$. Is there a standard discrete distribution with these moments and unbounded-on-the-right support, i.e., ...
0
votes
1answer
94 views
What kind of distribution is this?
I'm sorry is this is too obvious, but I'm having a hard time trying to find a distribution for my data. It is clearly not a normal distribution. It does not seem to be skewed, but seems to have fat ...
2
votes
2answers
97 views
What kind of frequency distribution is this?
I have a discrete frequency distribution, that looks like this
I am trying to find what type of distribution is it?
I looked at many models but it does not seem to comply with any.
I have 345 ...
2
votes
1answer
123 views
Are the data in this figure normally distributed?
What kind of distribution is figure 2 in this study? If it's a Gaussian distribution for the LH hormone, I can't make any sense of the data.
The article:
Aksglaede, L. et al. (2009): Recent decline ...
1
vote
0answers
56 views
What is the distribution of this Random Variable? I am expecting a Chi-Squared, but there is one term which is extra
I am trying to find the distribution o random variable $H$, but I am somehow confused.
The assumption is $M$ and $N$ are large enough (maybe around $100$).
When $L=1$, the distribution of $H$ is a ...
1
vote
0answers
63 views
Identify the underlying distribution from multiple samples
I have $30$ unequal samples ($n_i >1000$) from a supposedly same population. How should I go about identifying the underlying distribution of the population using these $30$ samples simultaneously?
...
1
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0answers
27 views
Distribution of relative proportions of draws from two uniform distributions
Drawing samples from 2 uniform distributions and calculating pairwise proportions of drawn values gives rise to a distribution I cannot recognize. What distribution is this?
...
1
vote
0answers
140 views
Determining the distribution of data
Hi, I am a student learning financial modelling. I would like some help in determining the distribution of the data given the plots above. I am reluctant to assume normal distribution of the data due ...
-1
votes
1answer
89 views
Which distribution is this [closed]
I know this will be a f distribution.But it's not f(m,n) since the square sign is outside the summation.So it will be f(1,n).But i can't seem to know how exactly.
0
votes
0answers
795 views
If this is a log normal distribution, how can I fit it?
The qualified question title hints at my not being certain as to what I'm really dealing with. I have some truly random samples that generate the following graph. This is just a small extract and ...
2
votes
2answers
158 views
How to determine the distribution iof this transformed variable $X_c = X ({1_{\{|X|>c\}}}-{1_{\{|X|\le c\}}})$
I have one question from econometric class which asks to find the probability distribution of the following:
$$X_c = X ({1_{\{|X|>c\}}}-{1_{\{|X|\le c\}}}) $$
where $X \sim N(0,1)$ and $c > 0$...
3
votes
0answers
74 views
Is this a known distribution?
For work, I plotted a set of shops by how many times they did business in the past week. The plot I got out looked something like this:
This looked obviously like a Pareto distribution. After all, ...
0
votes
1answer
138 views
KS, Anderson-Darling and Cramer -Von Mises don'y work on these data . Why? [closed]
I am using Mathematica to model the distribution of the data below and I test the fits with AD, CVM and KS but none of them seems to work I was told that my data may have an excessive amount of ties. ...
4
votes
2answers
2k views
How to determine the type of probability distribution for a dataset?
I have aggregated(total) youtube videos views. I have take log of that views. And calculated autoregressive koefs that can be used for the video views predictibility tests. Let say I have aggregated ...
0
votes
0answers
55 views
Looking for a good distribution to analyse market dynamics
I'm experimenting with replacement for normal distribution for my models.
So far, I tried Gamma and Inverse Gamma distributions. Gamma significantly underestimates the probability of the extreme ...
