Questions tagged [sample]
a sequence of objects or individuals collected from a larger (possibly infinite) population or process.
1,038 questions
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How to justify that testing 20 sprinklers (out of ≤5000) is a statistically meaningful sample?
In fire-protection maintenance, we often need to test a sample of sprinklers that have been in service for about 25 years.
Each test is pass/fail, and the parameter of interest is the failure ...
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Minimum recommended n per group in multilevel logistic regression?
Context:
I am running a multilevel logistic regression model with a random intercept by country (n=27) using Stata's "melogit". My goal is to examine if a group-level variable impacts the ...
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Probability of a failed component from an accepted component lot - tolerance analysis
Question: Given a component lot where a sample is drawn for testing leading to the determination of the sample mean and variance, a one-sided tolerance limit,$\mu + \mathrm{KTL} \cdot \sigma,$ is ...
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Correcting bias in covariance between a random variable and linear regression slopes from a finite sample
Note that I am performing a linear regression of a predictor variable $x_{i}$ with $i \in (1, 2 ..,m)$ on a response variable $y$ in a finite population of size $N_{t}$. Since the linear regression is ...
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Sample for rate outcome multiple treatment
I have to calculate sample size for a binary outcome. The question is about detecting a difference in outcome to four treatments that people are exposed too. Every person can be exposed to all four ...
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How accurate are the standard error formulas to find the standard deviation of the sampling distribution of a statistic?
1. Definitions
The standard error of a statistic is an estimate of the standard deviation of the sampling distribution of that statistic.
The sampling probability distribution of a statistic is the ...
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How can the standard error measure how accurately a sample represents the population, when we don’t have access to the population’s data?
If I got it correct, the standard error is a statistic that measures the variability of a sample’s data and how accurately a statistic represents the corresponding parameter.
Please suggest any ...
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Correcting $R^{2}$ of a sample linear regression, knowing the size of the population
Given a linear model of the type:
\begin{equation} \tag{Eq. 1}
y=ax + c + \epsilon
\end{equation}
I take a sample of size $N_{s}$ from a finite population of size $N_{f}$ and take the values of the ...
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Comparing a population odds ratio to a sample odds ratio
Is it possible to compare and quantify the accuracy of a population odds ratio to a sample odds ratio?
I have survey data that is sampled (stratified sampling by race and ethnicity categories) from ...
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machine learning for genomics data, more features then samples
Im an MD-PhD student.
I want to build predictions from data containing almost 20,000 features and 2700 samples, more or less.
I want help on which ML methods are recommended to use in this condition ...
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Does the Overall Margin of Error Decrease When Analyzing a Stratified Sample as a Whole? [closed]
In stratified sampling, if each stratum is designed with a fixed margin of error (MOE)—for example, 3% per stratum—does the overall margin of error for the combined sample necessarily decrease when ...
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How to measure the statistical significance of a change between two data vectors
Let's say I have 2 datasets of survey responses to 4 different questions. 1 through 7 is a numerical category from bad (1) to good (7). I want to compare how the distribution of responses changes ...
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Does the following maximum likelihood mean and variance result hold for all distributions?
Given a probability distribution $p(x \,|\, \mu, \sigma^{2})$, and $n$ independent and identically distributed draws $x_{1}, \ldots, x_{n}$ from the distribution $p(x \,|\, \mu, \sigma^{2})$, we may ...
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Difference in variance between sample mean of squares and square of sample mean
Suppose we have i.i.d. random variables $X_1 \ldots X_N$ from which we calculate a sample mean $\overline{X}$. I am interested in the quantities $Var[\overline{X^2}]$ and $Var[\overline{X}^2]$. Can ...
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Partially known outcomes and sample space
Consider a standard Bayes' theorem problem:
We have two boxes $A$ and $B$, and there is a radioactive material in exactly one of them. We have a detector that can detect the presence of the material ...
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