The bootstrap is a resampling method to estimate the sampling distribution of a statistic.
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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
...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 "...
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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 ...
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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 ...
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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:
<...
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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 ...
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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 ...
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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:
...
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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 ...
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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 ...
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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 ...
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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
$\...
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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 ...
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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 ...
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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, ...
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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 $...
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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 ...
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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?
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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 ...
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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, $\sqrt{p}$ ...
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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 (...
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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 ...
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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 $...
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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 ...
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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, ...
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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 ...
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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:
...
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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 ...
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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 ...
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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 ...
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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
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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% ...
