Questions tagged [stratification]
A sampling technique in which the population of interest is partitioned into subsets ("strata") based on characteristics known at all units before sampling.
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Should I normalise a sample drawn from a skewed population?
I am interested in the effect of the number of inhabitants of political entities on certain political behaviours within these entities. It happens that the number of inhabitants is not evenly ...
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How should stratification factors be accounted for in analysis?
In the context of a clinical trial with time-to-event primary endpoint, if stratified randomization is used for subject enrollment, how should the stratification factors be accounted for in the ...
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Interpretation of R output for stratified cox-ph model
For the following model:
model <- coxph(formula = Surv(time, status) ~ treatment * sex + strata(sex), data = data)
this is (part of) the model summary in R:
...
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a few questions on stratified analysis
If one of the 3 stratification factor from IWRS has data errors, should we replace it with CRF collected baseline values? Will this break the balance of the strata blocks?
For non ITT population, say,...
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Adjusting for stratification variables
In clinical trials, stratification may be used to ensure balance of treatments across covariates.
According to guidance documents (e.g. EMA/CHMP/295050/2013) stratification variables should usually be ...
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When and how of stratification?
I understand stratification at a novice level. For example, if we want to condition on gender in post experimentation inference, we might stratify or block on gender. As I understand it, we take each ...
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Stratified sampling across several variables individually
I am interested stratified sampling for the purposes of cluster validation. The purpose is to perform cluster analysis in a subset of the data and check to see if the precise distribution of variables ...
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Random permuted block sizes in a randomised clinical trial
What is the best way to choose the block sizes in a randomised clinical trial?
Randomisation for an ongoing trial is stratified by site (2 sites) and gender (m/f) for 4 strata - it uses random ...
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Studying more than one sampling unit in a single randomization
So we have a list of organizations that dedicate themselves to a certain social service.
Our goal is to ask both laborers and customers an overlapping(but not fully) set of questions for each one of ...
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Cluster sample or stratified random sample?
I've recently come across this problem in my textbook:
To gather information about the validity of a new standardized test
for high school juniors across the United States, a random sample of
20 high ...
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Do replicate weight, when the are available, supersede all the design-based procedures and analysis?
If the agency that conducted a survey and releases micro data at the individual or household level also supplies replicate weights for that sample, do these weights completely supercede any need or ...
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Confidence intervals around treatment effect in stratified experiment
Suppose you conduct an experiment, where a population is randomized and treatment is given to the treatment group and you are interested in covariates (stratification has been employed) and their ...
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Relative importance of equal sample size vs equal sample density
I am conducting a vegetation study of the effects of prescribed fire. I have an experimental area that will be burned and a control area that will not be burned. The experimental area has three types ...
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How to account for population stratification in Fisher test?
When performing a logistic regression this can be done by adding covariates. How could I do the same for a Fisher test?
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Power analysis for Blocked/Stratified design?
I'm curious how power analysis can be conducted when the scientist is stratifying on one or more variables?
I came across this approach but it went over my head. Ideally, the answer would not be "...
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