# Questions tagged [bootstrap]

The bootstrap is a resampling method to estimate the sampling distribution of a statistic.

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### “Recency-weighted” block bootstrap methods for time series sampling?

I have an "online learning" kind of application where I'm optimizing parameters for some objective which is calculated as an empirical risk over block-bootstrapped samples of a time series. ...
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### Ensemble averaging of statistics [closed]

I want to calculate statistics for 50 different combinations of measurements. For example, I want to calculate the the mean, median, percentiles, standard deviations etc. for 20 different measurements ...
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### After running a probit, how can I generate the margins for the whole distribution?

I'm using Stata. I ran a probit of the form $$\text{outcome}_i = \beta \ f(\text{income}_i) + \gamma\text{ Controls}_i$$ Where $f(\text{income}_i)$ is a fractional polynomial. I'm interested on the ...
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### Double bootstrap coverage failure?

I am working on a simulation to compare different bootstrap algorithms, like normal, percentile, BCa. I also include the double bootstrap or bootstrap-t, which requires a second round of bootstrapping ...
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### Block Bootstrapping t-tests in R with the residuals from a regression

I'm trying to implement a function for a block bootstrap for the residuals of a regression to then compute new t-statistics. ...
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### Bootstrap confidence interval for regression coefficients: Can they be calculated independently?

If y = a + bx the regression of interest and a and b are the parameters that you would like to estimate. From what I understand of bootstrap confidence intervals, the bootstrap is performed B times, ...
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### What's the right way to do Bootstrapping Analysis on UserId Randomized A/A?

My motivation is to do A/A analysis using the "Bootstrap" method to calculate the confidence interval of the "sample mean" (of treatment and control) of all metrics. In my A/B ...
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### Calculating a statistic via linear regression for a bootstrap procedure in R

I am interested in finding the interval estimate of the mean of my response variable when the predictor variable is equal to a certain value, that is $E[Y|X=x]$. The point estimate for this statistic ...
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### How to calculate coverage probability when the true distribution is unknown

I am trying to calculate the coverage probability of my bootstrapping method to know whether the method that I have is valid. However, all that i have is the samples, without knowing the true ...
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### Bootstrap confidence interval with mvrnorm - upper value equal to Inf

I am trying to predict a value and CI for two different treatments from a glmmTMB fitted model using posterior predictive simulations (mvrnorm function in the MASS package) as in the Salamander ...
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### Random Forest Confidence Interval via Bootstrapping

Background Suppose I have a trained random forest with $N$ decision trees. Given an input vectors $\vec{x}$, the prediction made by the $i$-th decision tree is denoted as $t_{i}(\vec{x})$. The ...
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### Boostrap estimator: sample or population?

As stated here: Do we use bootstrapping with population data? "The general idea of bootstrap is that by sampling from your data you re-create the sampling process that happened when sampling your ...
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### MonteCarlo function to Simulate and Analyse ARIMA Several Times

Here is the algorithm of what I want to do with R: Simulate 10 time series data set from ARIMA model through ...
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### A (new?) bootstrap-based technique to check if a model performs worse on “subpopulation”

This is sort of an ad hoc statistical test I've devised to assess the performance of a prediction model on different subpopulations I have a large sample A with a Subgroup R. I would like to tell if ...
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### What is the rational behind bootstrapping a model?

At this point, I understand what bootstrapping is and how it works. What I would like to understand better is the exact properties of the method regarding its test error and, as a related question, ...
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### Distribution of bootstrap and central limit theorem

Let's take a simple example: we have 100000 observations, and we want to estimate the mean. In theory, the distribution of the estimator is a normal distribution according to the Central limit theorem....
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### test the internal validity of this model / score by Resampling by Bootstraping

I am working on a predictive model of a diagnosis via a logistic regression "glm" Let me clarify right away, I am a medical doctor and researcher, not a mathematician, so sorry if I use ...
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### How to Use Parametric Bootstrap to Calculate Covariance Matrix? [migrated]

Using the following dataset "data": load(url("https://www.math.ntnu.no/emner/TMA4315/2020h/hoge-veluwe.Rdata")) I have fit a poisson GLM ...
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### Empirical distribution in bootstrap method

Fushiki (2005) states that [...] a nonparametric bootstrap sample $x^{* N}=\left\{x_{1}^{*}, \ldots, x_{N}^{*}\right\}$ [is] independently obtained from the empirical distribution \begin{equation} \...
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### Estimating distribution of tied ranks for tie correction to Wilcoxon-Mann-Whitney U test

Tests based on ranking elements, such as Mann, H. B.; Whitney, D. R. On a Test of Whether one of Two Random Variables is Stochastically Larger than the Other. Ann. Math. Statist. 18(1):50-60, 1947, ...
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### bootstrap gives conflicting results when simulate is used (LMER)

I perform a parametric bootstrap in 2 ways. first method: fit dataset in a H1 and H0 model(H1 contains all effects and HO has a certain effect omitted). retrieve the log likelihood ratio (call it here ...
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### Mann whitney and boostrap confidence intervals provide contradictory results

We are doing some a/b testing and have non-normal metrics so our typical t-test aren't appropriate. I typically use bootstrap CI and/or Mann whitney tests to determine the true effect. In this case ...
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### Can I replace mean with median if using the Central Limit Theorem and calculating p-value

I was reading this article ,article link here, about the Central Limit Theorem, CLT, and how it can be used to determine if a cohort of interest is significantly different than the population (I might ...
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### Why Bootstrapping standard errors and 95% confidence intervals change each time I re-conducted the analysis [duplicate]

I was using respondent-driven sampling analysis tool (RDSAT) to get bootstrapping confidence intervals. But each time I re-did the analysis, I noticed the bootstrapping standard errors and confidence ...
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### After bootstrapping regression analysis, all p-values are multiple of 0.001996

I'm running various multiple regression analyses in SPSS 27, and with those that are not bootstrapped, the p-values vary such that I do not find the same p-value twice within a regression (e.g., the p-...
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### Bootstraping with R, how to find possible bootstrap samples for a given vector

Consider the vector our_names <- c("John","Ciprian","Brian") a. List all possible bootstrap samples of our_names. b. How many ...
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### Use bootstrap mean to remove bias from the statistic?

I have a data sample on which I apply a statistic called "$\alpha$". I then use a standard bootstrap analysis on the data which results in something like this: As can be seen, the bootstrap ...
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### What is the distribution of the actual parameter given an estimate with credible interval or confidence interval?

Let's assume we have a variable $X$. Some authors said that X is distributed normally with mean $X_m$ with credible interval $(X_{m1},X_{m2})$ and SD $X_s$ with credible interval $(X_{s1},X_{s2})$. We ...
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### Estimating error when bootstrapping results are skewed

I'm trying to figure out the most robust way to estimate the error on the best-fit parameters of an exponential model ($y = x^a$) for some data. I have heard that bootstrapping is a solid way to ...
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### Bootstrap test stat for a vector of coefficients from several models

I have two non-nested multiple regression models say $A$ and $B$, and 10 different outcome variables on the same treatment units: $y_1,...,y_{10}$ and want to test whether the vector of 10 estimated ...
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### Do you have to set.seed when splitting data?

More specifically, in cases of bootstrap and cross-validation, we often tend to put a set.seed() randomly, either a number people like or more often 12 or 123. This ...
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### boundary (singular) fit: see ?isSingular during some iterations of bootstrap

I am performing a parametric bootstrap following this paper(section 4.5 step 4b): https://onlinelibrary-wiley-com.vu-nl.idm.oclc.org/doi/full/10.1002/cem.3232 when I iterate in my bootstrap, I ...
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### Permutation Hypothesis Testing procedure

I'm not strong in statistics and I'm looking for a help. I work with real estate data and I want to compare apartment prices in 2 districts: district "A" and district "B". Data ...
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### confidence intervals for fixed effects with reML

I am trying to asses wheter certain effects are significant in my mixed model. First I tried the confint function with the profile method and the Wald method. Both are somewhat similaire, now I want ...
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### Why residual bootstrap does not work for GLM?

My lecture note says Since we add residuals to the fitted model, this residual bootstrap only works for a homoscedastic regression model, where the error distribution does not depend on the ...
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### When and why should we bootstrap the standard error in regression?

I have a linear regression model: $$Y_i = \alpha + \beta_0T_i D_i + \beta_1D_i + \beta_2T_i + \delta x_i + \epsilon_i$$ where $Y$ is a continuous outcome variable, $D$ is the binary treatment variable ...
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### Creating a biased sample with two variables matching distributions from another dataset

I have a biased sample from a user activity dataset with known distributions of two variables, the amount of times a user logged in during last week (poisson distribution) and user's weekly revenue (...
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### What is the purpose of using duplicated data in resampling techniques (e.g., bagging/bootstrapping)?

With bootstrapping and bagging, we resample from the dataset and end up building a model or estimating some sample statistic using the sampled data, which typically consists of at least $33\%$ ...
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### How are bootstrap predictions properly reported?

I'm presently working on a paper in which bootstrapping is to be used. We plan to bootstrap our model's predictions and present these, as well as confidence intervals for the model predictions. When I ...
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### Correlated data series with single repeated value with a few outliers

I'm dealing with about 4,000 stationary time series, most of which I was able to reasonably fit to a distribution based on the KS test. About 200 of the time series, however, were not so well-behaved ...
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### Bootstrap for nonlinear regression and ranked explanatory variable

I've been wondering how the bootstrap method works in the case of nonlinear regression models where the order of the x-axis (suppose just 1 explanatory variable) matters. In the case of univariate ...
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### On Nonparametric bootstrap predictive distributions

Consider a model $p(x|\boldsymbol{\theta})$ which is trained using $N$ i.i.d. observations $X=\left\{x_1, \ldots, x_N\right\}$. Bayesian predictive distribution is defined as \begin{equation} p(\bar{x}...
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### Variance and CI for the difference in medians

One way to obtain a (1-alpha)% confidence interval for the difference in medians for two samples is to use bootstrapping. Generate 10,000 bootstrap samples of both group's samples and find the ...
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### An out of bag testing procedure I developed. Is it biased?

Trying to estimate the error of a prediction model trained on a combined group vs a subset of interest within that group (for example, Men) My procedure is First simulate a random subset like the ...
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### Obtaining p-value from bootstrapped Pearson's correlation using R

I am trying to carry out a bootstrapped Pearson's correlation using R software. I have 13 observations and originally I obtained: ...