FAQ/powerFAQ752019-01-16 12:17:26PeterWatson742019-01-16 12:09:14PeterWatson732019-01-11 16:43:48PeterWatson722017-06-22 11:11:37PeterWatson712017-02-07 12:30:58PeterWatson702017-01-05 16:09:52PeterWatson692017-01-05 16:05:51PeterWatson682016-04-04 10:09:13PeterWatson672016-03-22 10:31:44PeterWatson662015-11-02 15:39:14PeterWatson652015-08-20 14:48:06PeterWatson642015-04-27 16:02:32PeterWatson632015-04-27 16:02:18PeterWatson622015-01-27 16:56:46PeterWatson612014-11-10 12:17:38PeterWatson602013-03-08 10:17:16localhostconverted to 1.6 markup592012-08-23 12:34:57PeterWatson582012-06-26 14:39:15PeterWatson572012-06-26 14:38:58PeterWatson562012-01-05 15:28:48PeterWatson552011-07-27 14:28:05PeterWatson542011-07-27 14:02:47PeterWatson532011-03-21 12:29:27PeterWatson522011-03-21 11:42:06PeterWatson512011-03-21 11:41:50PeterWatson502010-07-22 12:44:17PeterWatson492010-07-22 12:41:53PeterWatson482010-07-22 12:09:33PeterWatson472010-07-22 10:08:25PeterWatson462010-07-02 11:14:56PeterWatson452010-04-15 14:33:28PeterWatson442010-01-28 15:55:09PeterWatson432010-01-19 12:43:28PeterWatson422010-01-19 12:42:57PeterWatson412010-01-11 16:57:56PeterWatson402010-01-11 16:53:56PeterWatson392009-11-13 11:30:50PeterWatson382009-11-11 12:15:43PeterWatson372009-11-11 12:15:30PeterWatson362009-11-03 16:07:05PeterWatson352009-11-03 15:31:17PeterWatson342008-04-28 15:07:44PeterWatson332008-04-24 15:49:17PeterWatson322008-04-24 15:47:52PeterWatson312008-04-24 15:35:49PeterWatson302008-04-23 09:27:02PeterWatson292008-04-23 09:15:02PeterWatson282008-02-11 16:39:15IanNimmoSmith272008-02-11 16:35:53IanNimmoSmith262007-10-18 13:13:15PeterWatson252007-10-15 10:33:27PeterWatson242007-08-13 15:37:17PeterWatson232007-08-09 15:11:17PeterWatson222007-08-09 13:46:43PeterWatson212007-08-09 13:18:39PeterWatson202007-07-17 14:40:13PeterWatson192007-07-13 11:01:26PeterWatson182007-04-04 14:45:04PeterWatson172007-04-04 14:37:37PeterWatson162007-04-04 14:33:21PeterWatson152007-04-04 14:32:35PeterWatson142007-03-16 11:15:34PeterWatson132007-03-16 10:58:59PeterWatson122007-03-02 11:30:40PeterWatson112007-03-02 11:28:01PeterWatson102007-02-01 16:22:21PeterWatson92007-01-05 10:15:30PeterWatson82006-12-15 17:18:10IanNimmoSmith72006-12-15 17:17:31IanNimmoSmith62006-12-15 17:14:30IanNimmoSmith52006-12-15 17:12:53IanNimmoSmith42006-11-29 15:46:49PeterWatson32006-09-29 13:26:32PeterWatson22006-09-28 15:54:38PeterWatson12006-09-28 15:27:59PeterWatsonQuestions about p-values, significance or power of testsCan I combine pilot data with main study data? When and how do I evaluate a one-sided p-value and quote a one-sided 95% confidence interval? What sample sizes do I need for doing tests with a given power? A guide to magnitudes of effect sizes Problems using p-rep, the Probability of Replication A quick guide to choice of sample sizes for Cohen's effect sizes A note on comparing z and t statistics and their p-values? How do I convert a t-statistic (and an Odds Ratio) into an effect size? How do I compute Cohen's d in SPSS and EXCEL and its and eta-squared confidence interval in SPSS, R or EXCEL? How do I compute Hedge's g from Cohen's d? How do I compute Mean Square Error (MSE) in EXCEL or SPSS? A guide to obtaining confidence intervals for effect sizes How do I compute effect sizes (including variance adjusted ones)? How do I do power calculations in SPSS, R, EXCEL and using web freeware? How do I do power (sample size) calculations on Poisson counts? How do I do power calculations using formulae for one sample t and sign tests? General rules of thumb for sample sizes in pilot studies How do I work out sample size for apriori specificities and sensitivities? How do I compute statistical tests of equivalence? Computing Power for ANOVAs using the SPSS GLM procedure Computing Power for ANOVAs using the SPSS MANOVA procedure How do I do False Discovery Rate (FDR) corrections for multiple tests? How do I calculate and interpret conditional probabilities? What is a p-value? How do I find p-values using critical values as input in SPSS and EXCEL? How do I adjust p-values for number of comparisons using SPSS and R? Adjusted p-values Combining p-values by Fisher's and Stouffer's methods Summing z values and summing t-values Why does the value of one in the F distribution have a p-value which is less than 1?