Questions about p-values, significance or power of tests

1. Can I combine pilot data with main study data?

2. When and how do I evaluate a one-sided p-value?

3. What sample sizes do I need for doing tests with a given power?

4. A guide to magnitudes of effect sizes

5. Problems using p-rep, the Probability of Replication

6. A quick guide to choice of sample sizes for Cohen's effect sizes

7. A note on comparing z and t statistics and their p-values?

8. How do I convert a t-statistic into an effect size?

9. How do I compute Cohen's d in SPSS?

10. How do I compute Mean Square Error (MSE) in EXCEL or SPSS?

11. A guide to obtaining confidence intervals for effect sizes

12. How do I compute effect sizes?

13. How do I do power calculations in SPSS, R, EXCEL and using web freeware?

14. How do I work out sample size for apriori specificities and sensitivities?

15. How do I compute statistical tests of equivalence?

16. Computing Power for ANOVAs using the SPSS GLM procedure

17. Computing Power for ANOVAs using the SPSS MANOVA procedure

18. How do I do False Discovery Rate (FDR) corrections for multiple tests?

19. How do I calculate and interpret conditional probabilities?

20. What is a p-value?

21. How do I find p-values using critical values as input in SPSS and EXCEL?

22. How do I adjust p-values for number of comparisons using SPSS and R?

23. Adjusted p-values

24. Combining p-values by Fisher's and Stouffer's methods

25. Summing z values and summing t-values

26. Why does the value of one in the F distribution have a p-value which is less than 1?