Details for Statistical Calculator

Hello again, interested parties!

Here is an excel file with a number of different statistical calculators I created.

1) 2x2 table - creates p-value for chi-squared test, Odds ratio and 95% CI, Risk Ratio (Relative Risk) with 95% CI and expected values to see if you need to use Fisher's Exact test instead. Use this to find associations between two dichotomous variables (i.e. Mortality and MRSA).

2) 3x2 table - p-value for chi-squared test of a 3x2 table - use this is one of your groups has 3 categories.

3) Diagnostic Tests - creates sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, pre-test odds, post-test odds, pre-test and post-test probilities.

4) Reliablility - computes a kappa statistic for measuring the agreement between two reviewers. For example if two people read multiple x-rays and you want to see if the results of the readings are in agreement between the two parties, you can use this.

5) Z-score - not often used but use this if you want to see the difference between two rates (be careful). It computes a Z-score which you then look up in the table to see the p-value. I have attached an article that shows you more about this in infection control (I used their formula from page 6).

Enjoy!

Tim
p.s. if you want anything else, let me know and ill see what I can do!