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Questions tagged [statistics-bootstrap]

In statistics, a bootstrap is a resampling technique based on random sampling with replacement.

The bootstrap was introduced by Brad Efron in the Late 1970s. It is a computer‐intensive method that enables enables researchers to estimate the sample statistics (such as medians, variances, percentiles) by drawing randomly with replacement from a set of available data.

See also:

  1. The Wikipedia page on Bootstrapping
  2. Bootstrapping using boot package in R
  3. Brad Efron's paper on bootstrap
  4. Review on bootstrap methods in econometrics
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Uneven observation length during bootstrap

As a relative beginner to R i am having difficulties. My goal is to bootstrap the individual coefficient of variation and to print that to a new dataframe for further calculations and analysis, eg 1000 bootstraped CVs for each individual based on…
Begga
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R: Distribution of Random Samples vs. 1 Random Sample

I have a question about random sampling. Are the two following results (A and B) statistically the same? nobs <- 1000 A <- rt(n=nobs, df=3, ncp=0) simulations <- 50 B <- unlist(lapply(rep.int(nobs/simulations, times=simulations),function(y)…
Brad
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boot.ci error message in R

I get All values of t are equal to 0.999999999999995 \n Cannot calculate confidence intervals My data is this: $data y x2 x3 1 2 1 1 2 0 2 1 3 -2 3 1 4 -4 4 1 5 -6 5 1 6 5 1 2 7 3 2 2 8 1 3 2 9 -1 4 2 10 -3 5 …
LoveMeow
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MATLab Bootstrap without for loop

yesterday I implemented my first bootstrap in MATLab. (and yes, I know, for loops are evil.): %data is an mxn matrix where the data should be sampled per column but there can be a NaNs Elements %from the array (a column of data) n values are…
Stephan Claus
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trying to use package bootstrap to run a jackknife on my Random Forest model

I'm having trouble trying to figure out the following: I am running Random Forest for classification of habitat use and have GPS data from 17 animals. My data frame depicts different habitat variables such as aspect and canopy cover at each used…
user3088823
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Deming Regression MCR package

I am using the "mcr" package for deming regression. When i try to use the functions mc.analytical.ci() mc.bootstrap() i get an errer saying "could not find function "(one of the two functions above)" " But I don't have any trouble using other…
user3819772
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Using for () loop or apply () to bootstrap means in a matrix

I have the following matrix (let's call it df), for which I would like to create bootstrapped means and 95% confidence intervals for each column, due to the heavily 0 weighted distribution. I would like the mean and CI's to be added to the bottom…
ctlamb
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Creating Bootstrapped Means and CI from matrix

I have the following matrix (let's call it df), for which I would like to create bootstrapped means and 95% confidence intervals for each column, due to the heavily 0 weighted distribution. I would like the mean and CI's to be added to the bottom…
ctlamb
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How to bootstrap a function after taking a randomly drawn sample without replacement

I have some code that allows me to take two randomly drawn samples from a dataset, apply a function and repeat the procedure a certain number of times (see below code from associated question: How to bootstrap a function with replacement and return…
jjulip
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How to bootstrap a function with replacement and return the output

I am trying to take two randomly drawn subsamples from a data frame, extract the means of a column in the subsamples and calculate the difference between means. The below function and use of replicate within do.call should work as far as I can tell,…
jjulip
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Bootstrapping function grinds to a halt, due to python pseudorandom generator?

I am working on a kind of bootstrapping procedure for visual fixation data, and would be helped by the insights of others on this issue I am having. I suspect that either I'm missing something related to the functioning of the random number…
drazulay
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How to implement bootstrap (resampling) in Java efficiently

I have a data file of 50,000,000 lines and need to bootstrap each line using Java. Right now I am using Math.random() to generate random number, then do the bootstrapping in a brute force way. However, it will take me forever. So i am wondering if…
Luna Park
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Bootstrap Confidence Intervals in R?

How can I compute 95% bootstrap confidence intervals for T.hat by the basic bootstrap confidence interval and the studentised bootstrap interval? failtimes<-c(3, 5, 7, 18, 43, 85, 91, 98, 100, 130, 230,…
user3347124
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Jaccard cluster confidence interval

I am hoping someone will give me advice on how to get confidence intervals from a Jaccard cluster using R. I have species data from the 1970's and from today at four sites. When I run the following code I get a great graph that shows that one of my…
MyNameisTK
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How to implement the bootstrap in R

So I posted a thread about this problem, but it got on hold. So I rephrased so it can be it a programming question. This is my code below. I am trying to find the stimulated confidence level of a sample using the bootstrap. # Step One: Generating…
user3295513
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