Page built from things in the old psyctc.org site 4.i.19, updated 8.i.19. All content is made available under a Creative Commons License. Please feel free to reuse anything here but respect the licence, i.e. give attribution back to here.
I’m not sure when I first started mounting these calculators, certainly by 2003. These compute the confidence interval (CI) for observed sample statistics using the sample statistics and the sample size. The default CI is 95% but you can set other spreads if you want them. For continuous value statistics these are parametric model CIs based on Gaussian distributions, for rates these are the best performing methods for the CIs as far as I can work out from R documentation and my reading).
- confidence interval of a proportion Mounted 12.viii.03.
- confidence interval of a difference between two (independent) proportions Mounted 14.viii.03.
- confidence interval of a mean from mean, s.d. (or s.e.) and sample size (n). Mounted 16.viii.03, last updated 22.xii.03.
- confidence interval for Cronbach’s alpha from the observed value, n and the number of items (k). As of 8.i.19 I have two forms for this, the old one calling R via the CGIwithR package running on the site server and the new one that uses the shiny package within R running on the Rstudio shinyapps.io server. Please use both and let me know if you find differences and also let me know how much of the explanatory text in the old version should be transferred into the new version.
- Program to compute the confidence interval around an observed (Pearson or Spearman) correlation coefficient. Requires observed value and n.
- Program to compute the meta-analytic confidence interval around observed (Pearson or Spearman) correlation coefficients. (There are probably much better ways to do this that are much more widely available than they were when I wrote this about a decade ago. I will come back to this one!)