Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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

0
votes
1answer
29 views

Explanation of confidence interval from R function boot.ci

I used boot function in R to do bootstrap for 40 times and used boot.ci to get the "normal" confidence interval. The following is my R code: 1. Define the statistic used in boot function ...
0
votes
0answers
20 views

Hypothesis testing with repeated measurement on same population and with non-overlapping partitions per case

Having a population of $N$ individuals, I calculate an outcome variable $y$ for those who have a characteristics $x$ and those who don't have $x$ as a characteristics. This partitions the N ...
0
votes
0answers
10 views

Regressions with fixed predictors and many permutations of the response data - how to present results?

I have a large matrix of species community abundances from many sites (species in columns and site in rows). I also have environmental variable for each site, and am using linear mixed effects models ...
0
votes
1answer
44 views

Dealing with small sample size

The objective is to classify a variable Y which is binary, outcomes [0,1], where all the features $X_1$....$X_{156}$ are normalized and continuous. The methods I'm using are Logistic regression and ...
0
votes
0answers
15 views

How to use bootstrapping in R with a k-sample Anderson-Darling test [on hold]

I have used an Anderson-Darling test (ad.test from kSamples package) in R to test whether two sets of samples come from one common distribution. They are different in number (n = 38 and n = 137). They ...
0
votes
0answers
12 views

Errors using boot() and boot.ci (parametric vs. non-parametric) [closed]

I'm pretty new to R and bootstrapping, so I'm having trouble understanding where this is going wrong. Below is my full code I am using. For this dataset I want to do both non-parametric and parametric ...
0
votes
0answers
18 views

Bootstrap resampling, oob

I'm currently reading about bootstrap resample and as far I'm concerned, if you have 150 "real" observation, the bootstrap method will randomly take one of the samples, add it to your just created "...
0
votes
0answers
16 views

How can I run a decision tree algorithm with a specific hierarchy of variables and with many missing values?

I asked students in learning groups what their biggest learning problem was "today" for each learner. The biggest problem could either be "motivational" (=motivation problem) or cognitive (="knowledge ...
0
votes
0answers
11 views

bootstrapping covariance matrices with different sampling procedures

The regression model has heteroskedasticity. The variance of error term depends on regressors. From boostrapping analysis, I got two different covariance matrices of $\beta$. The difference results ...
0
votes
0answers
9 views

Using abcnon bootstrap function on bivariate problem (regression) [closed]

The examples for the non-parametric bootstrap function "abcnon" in the R package, "bootstrap", are all univariate. How do you define the input function to use more than one variable. As an example: <...
0
votes
1answer
25 views

Number of bootstrap replicates versus number of simulations

I have some confusion over bootstrap simulation in R. Here is the question: I am asked to use the following parameters to produce simulation: 500 bootstrap replicates 1000 simulations Sample size of ...
1
vote
0answers
12 views

plots to show whether the observed data is contained within a distribution

library(dplyr) library(ggplot2) df <- data.frame(year = 1980:2014, y = rnorm(35)) For each year, I have a model that predicts ~5000 values of ...
0
votes
0answers
14 views

Trying to understand the boot function and bias in R

I have the following code with the assistance of package "boot", it is very simple so I can learn and you can teach me more effectively: ...
0
votes
0answers
15 views

definition of a bootstrap [duplicate]

I am doing the following and am not 100% sure I can call it a bootstrap: I have a distribution (fp) of points p1,...,pn. And I have one point P. All points are located on the same 2-dimensional ...
0
votes
0answers
6 views

Implications of bootstrap resampling on optimal DOE evaluation

Background: I have a set of experiments that include some D-optimal DOE points, and I am trying to use bootstrap-resampling to get an estimate of the value of having those points in the analysis ...
1
vote
0answers
10 views

Non-independence of bootstrap samples

Background Suppose we have a dataset that consists of $n$ iid random variables represented as $X_j$, where $j \in \{1,\ldots,n\}$. We know $\forall i,\, \operatorname{E}\left(X_i\right) = \mu$, and ...
0
votes
1answer
13 views

Expectation and variance of bootstrap samples

Background The data at hand consists of $n$ iid random variables represented as $X_j$, where $j \in \{1,\ldots,n\}$. We know $\forall i,\, \operatorname{E}\left(X_i\right) = \mu$, and that $\...
0
votes
0answers
22 views

Diagonal straight lines in residual vs predicted values: can it be fixed with bootstrap resampling?

I am studying a health-related-quality-of life scale and I run a multiple linear model for each of its subscales. For a few of these subscales I came across the pattern of several diagonal straight ...
1
vote
1answer
22 views

Different answeres doing essentially the same method

I want to do a bootstrap in two ways and compute the estimated bias and variance. The dataset I use is named Data and it is just $n=100$ randomly generated gamma ...
0
votes
1answer
22 views

Bootstrap clarification of question

Ok I've been trying to interpret what they actually want me to do here, I've been sititng with this exact question for 1,5 days now: What confuses me is the sentence "Draw 1000 samples of this size, ...
1
vote
1answer
49 views

Trouble understanding some r code

I have this code here (it's out of a book called "An Introduction to Bootstrap Methods with Applications to R") We are working with the estimator: $S_n^2=\frac{\sum_{i=1}^{n}(X_i-X_b)^2}{n}$ where $...
2
votes
2answers
51 views

Determining power of statistical test through bootstrapping

I'm trying to understand what's happening in the article Using simulation to estimate the power of a statistical test I'm familiar with bootstrapping which makes sense to me. But I don't understand ...
1
vote
1answer
37 views

Bootstrap in models with dummy variables

I have applied the bootstrap technique in a multiple regression model where some dummy variables are included, is there anything special about the treatment of dummy variables?
3
votes
0answers
24 views

How bootstrap sampling cause bias in Random Forest?

I am confused how bootstrap sampling causes bias in the feature selection process of Random Forest. In this article, it says "Obviously, the bootstrap sampling artificially induces an association ...
0
votes
0answers
14 views

Difference between Random Forest and Random Subspaces/Patches

When fitting a Random Forest model, a subset of the features is randomly considered at the splitting of each node. E.g., if $p$ is the number of features, then at each node in each tree, $\sqrt{p}$ ...
1
vote
0answers
57 views

Two-sample bootstrap hypothesis test

I am a beginner so please be indulgent. I would like to use a two-sample bootstrap hypothesis test for difference of means to this scenario: the impact of a new tool on team members daily output (...
0
votes
1answer
15 views

Robustness of ranking based on cross validation set, should I bootstrap?

I have a dataset that I separate into training and validation. I fit several models on the training set and then evaluate their performance on the validation set. When I rank the models based on their ...
1
vote
0answers
21 views

How to Bootstrap the Power in a Regression Hypothesis test

I am running a regression $Y=\beta X$ having several covariates, and my hypotheses are: $H_0$: $$\beta_1 = 0$$ $H_a$: $$\beta_1 \neq 0$$ I want to use the bootstrap to compute the power of the test $...
0
votes
0answers
15 views

bootstrap correlated data intuition

To estimate the variance of a parameter, I know that a simple bootstrap will not work for correlated data. I also read about block bootstrap. I am trying to get an intuition about why it is necessary ...
0
votes
0answers
10 views

Are test conditions not relevant when bootstrapping?

I'm reading about bootstrapping and permutations with R, and came across a book comparing simulation based methods to the traditional approach (https://moderndive.netlify.com/b-appendixb). In section ...
3
votes
1answer
29 views

Bootstrap Confidence Interval, f-value and p-Value

I am trying to understand the intricacies of Linear Regression (1 predictor, 1 response). I am using Istanbul Stock Exchange dataset (https://www.kaggle.com/uciml/istanbul-stock-exchange) to do the ...
0
votes
0answers
7 views

Does it make sense to age-standardize my sample using a direct method if I'm already using bootstrap weights?

I'm new to statistics and this website, so let me know if there's anything I should change in asking this question. I'm combining 10 years (collected annually) of national survey data to look at ...
1
vote
2answers
31 views

How to determine statistical significance of mean being larger than zero?

I have a set of numbers generated by an unknown to me random distribution. When I calculate the average of these numbers, I get a number that is larger than zero. I want to know how likely it is that ...
0
votes
0answers
21 views

Mediation: Significant indirect effect, but total effect nonsignificant, no inconsistent mediation

I conducted a mediation analysis via lavaan. For estimating all effects, I used 10,000 bootstraps. I have problems interpeting my results. Path a is negative and significant. Path b is positive ...
0
votes
0answers
12 views

Bias of a function of the avarage

It's well known that $\overline{x}$ is an unbiased estimator of the exact average. Now, we let's imagine that we want to estimate some function of the average $f(\langle x \rangle)\equiv f(X)$. My ...
-1
votes
1answer
22 views

Binary significance testing on sex [closed]

I have a data set of 10,000 patients (roughly). Around 6300 are women and 3700 are men. Is there anyway for me to say that within this patient group, a randomly selected patient is significantly more ...
0
votes
0answers
18 views

Bootstrap and Prediction Confidence Interval

I have a question about how to use bootstrap to generate the confidence intervals for my model predictions. I do not care about the confidence intervals of the single parameters of the model (indeed, ...
0
votes
0answers
18 views

Repeated measures and bootstrap

I have data from 100 individuals where: 100 got test 1 50 got test 1 and 2 The outcome is binary I've just started statistics this summer, and was told to use a generalised mixed model to check for ...
1
vote
1answer
51 views

Using bootstrap to estimate the 95th percentile and confidence interval for skewed data

The problem: I have data of sales per day during a certain period (n=7939). The data is rather skewed (see the first image below). I would like to propose the number of items to resupply every day ...
1
vote
0answers
26 views

Testing the significance between two correlations in Python.

I've seen some similar articles using R but I'm not sure how to implement this test in python. Suppose I have two datasets, A and B (both contain 35 datapoints), and they predict some time series of ...
0
votes
0answers
34 views

Linear model from iterative process in R

I would like to test a relationship between to factors such as birds occurrence and temperature for instance, to test if temperature affects birds occurrence from a country (e.g. Germany). I have a ...
0
votes
0answers
40 views

Boostrap sample distribution of a parameter versus bayesian interval

I was hoping someone could give a simple explanation of the difference between a bootstrap interval for a parameter and one obtained from MCMC sampling of the posterior. Specifically, suppose I have ...
0
votes
0answers
21 views

Enzyme kinetics: Bootstrapping parameter estimates

First things first - this is kind of a mixed problem from biological data analysis, I hope I am in the right place to ask my question(s). Context I have data from a fluorescence assay of binding of ...
3
votes
1answer
112 views

Bootstrap intervals for predictions, how to interpret it?

I want to come up with a way to get how confident I am in my predictions. I am not using a Bayesian model so I was thinking a bootstrap confidence interval would be good: I would re-sample my ...
0
votes
0answers
18 views

Sample size of each resample

I am calculating a performance metric based on the resamples obtained from cross-validation and bootstrap using the R-package caret: ...
0
votes
0answers
20 views

Confidence interval of median difference, SPSS

Despite some great help on here I'm not 100% sure about calculating 95 CIs for median difference. This is my procedure at the moment. I've got a repeated measures design, so behaviour of animals in ...
1
vote
2answers
42 views

When is bootstrapping helpful and used?

When is bootstrapping helpful and when should it be used? I have watched several videos so I understand what bootstrapping does (samples with replacement from a single sample many times and create a ...
0
votes
0answers
13 views

Hypothesis perturbation Bootstrap Z testing on unequal sized data sets

Note I am solving this problem in python3 Question: records on the amount of a TV channel watched are given for people who decided to buy a product vs those who didn't buy the product. (The product ...
1
vote
0answers
13 views

Bootstrapping quantiles from an estimated binary outcome

I am trying to predict a binary outcome that is unobserved but I have made bootstrap estimations of its value. As a result I have bootstrapped training data where the outcome for the same observation ...
3
votes
0answers
34 views

Meta-analysis using bootstrapped confidence intervals (non-normal data)

I have the results of two studies (my own and a previous study). I want to perform a small meta-analysis to obtain a better estimate of the effect size. For the two studies I have the means and 95% ...