6
votes
Why do confidence intervals width increase when sample size increases "a bit"?
A standard confidence interval for a mean is calculated using $s/\sqrt n$. If you increase $n$ but also increase the sample standard deviation $s$ by enough to offset the larger sample size, then your ...
- 32.5k
2
votes
Number of observations for multiple linear regression
For this type of 3-level predictor you only would specify 2 dummy variables and have the 3rd (reference) level represented by having 0s for all the other levels. The reference level is thus ...
- 64.4k
2
votes
Sample size calculation for moderated moderation (three way interaction: continuous x continuous x continuous)
The main difficulty with the simulation is that accurate specification of all parameter estimates is difficult as we don't have a good idea of the magnitude of the parameters.
I see that as a ...
- 64.4k
1
vote
Accepted
If I need to reduce my sample size due to computation time, should I standardize using my original or post-reduction means and standard deviations?
Likely it should not matter. If taking every 100th point is essentially a random sample from the larger population, the means and variance estimates should be more or less the same. If there is ...
- 1,599
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