Questions tagged [empirical-cumulative-distr-fn]
Empirical cumulative distribution function: a step function increasing by $1/n$ at each unique $X$-value that occurred in the sample.
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questions
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Standard Errors of ECDF with Potential Model Fit Error
I have data and a proposed likelihood. I used MLE to fit the likelihood, but it is a very complicated likelihood and there is some estimation error of the model. The likelihood may be correct, but ...
6
votes
1answer
145 views
What are the simplest examples of nonlinear statistical functionals?
I am reading Wasserman's book "All of Statistics" in which he defines a statistical functional as any function $T(F)$ of the cumulative distribution function $F(x)$ that outputs a real ...
2
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1answer
23 views
Picking a specific estimated CDF from a set of CDFs provided by an ECDF
Let $F_X$ be a CDF of an unknown random variable $X$. If we have independent samples $x_1, x_2, \ldots, x_n$ of $X$ then we can estimate $F_X$ non-parametrically using an ECDF $\hat{F}_n$. By Central ...
2
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2answers
58 views
Notation for ECDF
I'm reviewing statistical functionals and U-statistics, trying to make notes, and I am tripping on notation. From my understanding, $X$ is used to denote a random variable and $x$ is used to denote an ...
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0answers
14 views
Trying to interpret the comparison between two ECDF curves
I am trying to understand ECDFs to compare two models "a" and "b". My initial interpretation from the plot is that judging by the difference between the two curves model "b&...
2
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1answer
119 views
Density estimation from ECDF - numerical derivatives and scaled domains
Suppose we want to get a density estimate of some data X. One way is to compute the empirical CDF,
...
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0answers
19 views
Bootstrap bias-corrected percentiles
Following [1] p. 185-186 the $BC_a$ (bootstrap corrected and accelerated) confidence intervals are given by:
$$
(\hat{\theta}^{*(\alpha_1)},\hat{\theta}^{*(\alpha_2)}),
$$
where $\hat{\theta}^{*(\...
2
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0answers
21 views
Nonparameteric Empirical Estimator For Stochastic Process
Motivation: If $X$ is a random-variable defined on some probability space $(\Omega,\Sigma,\mathbb{P})$ then Glivenko-Cantelli lemma guarantees that the empirical distribution $\frac1{N}\sum_{n=1}^N \...
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20 views
Kolmogorov-Smirnov (KS) test two-sample eCDFs and Dmax
I am running the two sample KS test to see whether two models are similar or not. Now the KS test does give me the answer to my question. But I have a question regarding the eCDFs and Dmax computed by ...
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0answers
7 views
Understanding of scale loss with Gaussian prior
I am reading a paper called PHOSA wherein a scale loss is used. I had the following questions regarding this scale loss in equation 8:
What part of this loss function is actually incorporating a ...
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0answers
26 views
How to deal with a PDF that takes CDF data as input? (Metalog distributions)
I am trying to utilise the Metalog distribution in a Machine Learning project.
For this project, I need to be able to obtain likelihoods using the PDF of the distribution.
https://en.wikipedia.org/...
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18 views
Convergence of the first moment of empirical distribution
Imagine I have a sequence of random variables $\{x_n\}_{n=1}^{\infty}$. These are not i.i.d. random variables, but an arbitrary sequence.
For any $n$, I can define the empirical CDF function $F_n(t) = ...
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13 views
Reverse Cumulative Frequency explanation
I've been seeing a lot of Reverse Cumulative Frequency (RCMF) plots lately and trying to figure out how to understand the way reverse cumulative frequencies are calculated, and the interpretation of ...
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0answers
32 views
Is it possible to convert a pdf obtained with density() to an ecdf?
Consider the following code that gives us (an estimate of) the pdf of a random variable $X$:
X = rnorm(100,10,1)
XDensity = density(X)
I want to obtain the ecdf of ...
2
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0answers
38 views
Fitting a function to ECDF [closed]
I have some ECDFs. I would like to summaries the ECDFs with functional approximations. I was thinking that a polynomial, spline, or other line fitting procedure would generate a nice parsimonious ...
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19 views
Computing the most representative sample of a random variable
Let $X$ be a real-valued random variable and $n > 0$. Using numerical methods, how can we find the vector $\vec v$ of $n$ real numbers that is most characteristic of $X$, in the sense that the ...
3
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1answer
57 views
Median from two unmergable datasets
I am trying to calculate the "overall" median of a variable that is spread across two datasets. I have access to the raw data in each dataset but can't bring their raw data together. What ...
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0answers
69 views
Why are people using KS statistic to choose cutoff for binary predictions?
I've seen that people are sometimes using Kolmogorov-Smirnov statistic to determine a cutoff in a binary classification models, such as logistic regression. However, i do not fully understand why and ...
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1answer
38 views
Obtaining an expression for empirical mean from empirical CDF definition
This is my first post so I will try to be as clear and concise as possible. I am doing a course in statistics and we define the true mean of a random gaussian variable to be as follows:
$\mu$ = $\int_{...
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1answer
137 views
Confidence Interval of p-Quantile from Empirical CDF
I am trying to provide an interval estimate for the 0.8-quantile of some numeric data, which is assumed to be an IID sample from some unknown, continuous distribution. I constructed an Empirical CDF ...
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0answers
45 views
Calculating the quantile of random forest test cases
I want to calculate the quantile of the observed value of a test case with respect to the prediction interval generated from a random forest, so for each test case I want the proportion of the ...
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0answers
21 views
Goodness of fit methods for density estimation
If we want to estimate the probability distribution function (pdf) of finite-sampled real continuous data using one of the following approaches:
Parametric density estimation: fit a well-known ...
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0answers
40 views
Empirical estimation of conditional distribution $Y|X$ at the boundaries of X
I want to estimate conditional distributions of Y | X. Where X contains several continuous covariates.
I'm coding in R. I tried several methods so far, but none gives me entirely satisfactory results ...
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1answer
50 views
Does the Glivenko-Cantelli theorem work back and forth?
If we have a sample $X_1, X_2, \ldots, X_n \sim F$ then $\hspace{1mm}sup_x|F_n(x) -F(x)|\xrightarrow{a.s./p}0$.
Now, if I can come up with a theoretical cdf $F$ such that $\hspace{1mm}sup_x|F_n(x) -F(...
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91 views
Is it accurate to take the maximum distance between CDF and ECDF only at the edges? (Kolmogorov-Smirnov Test)
I have two samples, one obtained empirically and the other is the result of a simulation. I want to tune the simulation so that the result resembles the reality, for that I will minimize the KS ...
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1answer
94 views
Example of cumulative distribution function and the empirical distribution function [closed]
A random of 100 rolls of the die. The outcomes 1, 2, 3, 4, 5, 6, occurred 13, 19, 10, 17, 14, 27 times, respectively. Calculate the cumulative distribution function and the empirical distribution ...
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1answer
188 views
How can i find empirical survival function using survival function in R?
The survival function is given by:
S(y; α, λ) = (α/α−1)* (1 − α^(−e^(−λy ))), if α is not equal 1
= e^(−λy) if α =1
y = 1 4 4 7 11 13 15 15 17 18 19 19 20 20 ...
37
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4answers
2k views
Intuitive explanation of Kolmogorov Smirnov Test
What is the cleanest, easiest way to explain someone the concept of Kolmogorov Smirnov Test? What does it intuitively mean?
It's a concept that I have difficulty in articulating - especially when ...
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0answers
26 views
Predicting probability of failure mid life with weibull or ecdf
thank you for taking a look at this. I have failure data for tires over a 5 year period. For each tire, I have the start date(day0), the end date(dayn), and the number of miles driven for each day. I ...
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0answers
142 views
Comparing empirical distributions with an interaction effect
My experiment includes two subject groups: group1 and group2. Both groups undergo a behavioral test, the result of which is called “movement celerity” (this is my dependent variable). Both groups are ...
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1answer
31 views
Fit cdf and pdf from points on empirical cdf
I have cumulative counts with respect to a variable x, which looks like:
...
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1answer
51 views
Can we apply the Probability Integral Transform to Dependent Random Variables?
Let's suppose we deal with a non-homogeneous Poisson process having intensity function λ(t), t ≥ 0. The event times X1, X2, … of ...
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1answer
42 views
How to perform van Zyl's (2018) ecf-based normality test in R [closed]
I have been reading quite a bit on empirical characteristic function (ecf) based normality tests, but cannot find any functions to perform such a test in R and lack the mathematical ability to figure ...
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0answers
34 views
What are “absolute ECDFs” called (if anybody uses them)?
By absolute ECDF, I am referring to an ECDF that shows the absolute number of samples above some value as opposed to the fraction of such samples.
For example, the bottom plot below displays such an ...
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0answers
20 views
Quantile-calculation example: Why the term $c$?
I need help to interpret a solution to the following example:
Based on historical claim amounts $x_1,...,x_{47}$, which are assumed to be outcomes from an unknown claim distribution, you are ...
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2answers
292 views
Simulate data from ECDF in R [closed]
Consider the following 11 continuous non-negative observations:
0, 0.3, 0.31, 0.33, 0.37, 0.49, 0.51, 0.53, 0.59, 0.6
Obtain the empirical cumulative distribution function for these observations.
...
2
votes
1answer
70 views
How to quantify distribution concentration in cdf? [closed]
For example, let's say I have a list of users, each user has its revenue.
I can plot the cdf of both user and revenue, to see if there is some concentration, for example, may be 40% user contribute ...
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0answers
88 views
Measuring distance between cumulative distribution and empirical distribution
What is an easy to understand step by step procedure on how to compute a distance between a cumulative distribution function and an empirical distribution function given a random sample using ...
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3answers
993 views
Confidence Interval of CDF
I am trying to determine if there is a statistically meaningful distinction between the cumulative probability density curves shown in the figure below.
It's simple enough to do a $t$-test on the ...
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0answers
30 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 ...
2
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0answers
38 views
What linear transformation minimizes the Kolmogorov–Smirnov distance between two sets of points?
Suppose we have two sets of real-valued points $X_1, \dots, X_m$ and $Y_1, \dots, Y_n$. We want to find the linear transformation that makes the distributions look alike. If we want them to have the ...
4
votes
1answer
330 views
MLE as an expectation over the empirical distribution
I am reading Ian Goodfellow "Deep Learning" book. At page 128, it writes the maximum log-likelihood estimator and then says it is equivalent to the expectation over the empirical distribution
To ...
5
votes
1answer
251 views
Maximum likelihood as minimizing the dissimilarity between the empirical distriution and the model distribution
I am reading Ian Goodfellow "Deep Learning" book. At page 128 it says
One way to interpret maximum likelihood estimation is to view it as
minimizing the dissimilarity between the empirical ...
0
votes
1answer
36 views
Determine significance of an observed value
I have an ECDF of values that do not follow a particular distribution (thought they are slightly normal, they are not). And I wish to determine if a new observed value is significant or an outlier or ...
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0answers
46 views
Empirical 1-sigma confidence interval
I would like to construct a 1-sigma confidence interval for my 1D data. I don't know the underlying distribution, and it is strongly skewed, so standard deviation will not suffice. I see that people ...
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2answers
278 views
Fitting a normal CDF using proportion data
I have the following data (prop is like empirical CDF):
...
3
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2answers
290 views
Can some one give a step-by-step computation for an empirical distribution with this concrete example
This post gives this formula to compute the empirical distribution:
\begin{equation}
\hat{p}(x) = \frac{1}{m} \sum_{i=1}^m \delta(x - x^{(i)}) \tag{3.25}
\end{equation}
I am trying to compute this ...
0
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1answer
1k views
obtaining empirical CDF of a given data
I have a dataset of variable $x$ that has a value between 0 and 6. I would like to have a function that defines empirical CDF of variable $x$. Since $x$ does not have a specific distribution (such as ...
0
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1answer
248 views
Is the Cumulative Hazard Function simply estimated using the Empirical CDF?
I'm just starting to learn about Survival Analysis and I understand the theoretical proofs but I'm still unclear about how to do some of the estimations practically.
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0answers
93 views
R: Calculating the convolution of two (multivariate) functions using FFT
I'm looking for a way to calculate:
$$(f\ast g)(x) = \int_{\mathbb{R}^d}f(y)g(x-y)dy$$
in R. I have solved this problem using Monte-Carlo integration. However, ...
