# Tag Info

### Sample Size impact on Effect size

When your sample size is small, there will be more sampling error attached to your effect size estimates and hence more uncertainty/wider confidence intervals. In that sense, I wouldn't say the effect ...
• 3,196

### Sample Size impact on Effect size

As long as the sample is random, the estimate of the effect size is unbiased even in small samples. However, other things being equal, it will be less precise. It's still your best guess, but the ...
• 117k

### Determination of sample size vs. repeated measurements in experimental design

Repeated testing of one widget will allow you to determine the magnitude of measurement variation (noise) and, maybe, if there are time or test-dependent changes in the performance. Those things are ...
• 14.9k
Accepted

### How to calculate sample size from hazard ratio?

The key reference here is Schoenfeld (1983), who gives the following formula: $$\frac{(z_{1-\beta}+z_{1-\alpha})^2}{pA\times pB\times\text{log}(\text{HR})^2}$$ This will give you the number of ...
• 3,658

### Sample Size impact on Effect size

All things being equal, the major difference is the variation in the effect as a function of sample size. A very simple simulation in R shows this as the case. Here I simulate two groups who have the ...

### Sample Size impact on Effect size

The question is fully addressed by meta-analysis (see, e.g., Introduction to Meta‐Analysis by Borenstein et al.), which includes studying of how the effect size vary from one study to another. Indeed, ...
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### Seeking Papers with Significant Associations in Univariate but not in Multivariable Analysis Due to Sample Size

You are comparing two different things: Univariate analysis assesses marginal distribution, whereas multivariate analysis assesses conditional distribution. They answer different questions. Both ...
Accepted

### Calculate sample size in an experiment with interactions

This looks like a two-way ANOVA disguised as a three-way ANOVA. The critical things I see that you are testing are these two factors: The effect of stimulation. The effect of treatment. (Optional) ...

### Are there coventions on reporting weighted sample sizes?

I assume you will report weighted averages or proportions. Usually weights are based on a reference population,eg, the United States or New York City. This basis for weights should be reported. ...
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### Small-sample binary logit and linear models - response to referees

I do not think the problem comes from the small sample size per. It rather comes from the fact that MPs are obviously almost present everywhere regardless from the value of explanatory variables, ...
• 615

### Small-sample binary logit and linear models - response to referees

There is no fix for this situation. Not only has the experiment used a minimum information (binary) response variable, but it does not have the needed sample size (96) just to estimate the intercept ...
• 90.5k
1 vote

### Small-sample binary logit and linear models - response to referees

Can we still use a multi-factor logistic regression model? 2. The results of the single-factor logistic regression analysis suggest that the D-dimer concentration index has statistical significance (P=...
• 1,454
1 vote

### Small-sample binary logit and linear models - response to referees

The usual rule of thumb with logistic regression is that you can include one IV for every 10 cases in the less common case. For you, that's six people, so this rule would say "One IV at most"...
• 117k
1 vote

### Determination of sample size vs. repeated measurements in experimental design

I want to compare the performance of two versions of a widget using a 2-sample comparison test. H_0 = both versions perform the same, H_1 = widget.b performs worse than widget.a. Your hypotheses ...
• 1,454
1 vote

### Sample Size calculation - “subgroup hypothesis”, Guidance needed

Quite a few question here, I'll provide some thoughts. Powering for overall vs. subgroups Unless the operating characteristics line up through (very unlikely) chance, you'll have to choose between ...
• 3,658
1 vote

### superiority margin in sample size calculation

An appropriate method depends on the details of your planned analysis. You have to look carefully at the documentation of these calculators to see if they are fit for your purpose. The first link (...
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1 vote

### Record all influential factors even at high n?

This is a cool use-case of applied causal inference! To answer your question directly: If there is no confounding and you have sufficient samples, causal inference is definitely a lot easier and you ...
• 2,084
1 vote

### Seeking Papers with Significant Associations in Univariate but not in Multivariable Analysis Due to Sample Size

It would be interesting to see a simulation meeting your criteria. Usually in practical settings, the more variables you have the more probable it is that you will find the relationship between ...

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