<?xml version="1.0" encoding="utf-8"?><!DOCTYPE article  PUBLIC '-//OASIS//DTD DocBook XML V4.4//EN'  'http://www.docbook.org/xml/4.4/docbookx.dtd'><article><articleinfo><title>FAQ/powerFAQ</title><revhistory><revision><revnumber>75</revnumber><date>2019-01-16 12:17:26</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>74</revnumber><date>2019-01-16 12:09:14</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>73</revnumber><date>2019-01-11 16:43:48</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>72</revnumber><date>2017-06-22 11:11:37</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>71</revnumber><date>2017-02-07 12:30:58</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>70</revnumber><date>2017-01-05 16:09:52</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>69</revnumber><date>2017-01-05 16:05:51</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>68</revnumber><date>2016-04-04 10:09:13</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>67</revnumber><date>2016-03-22 10:31:44</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>66</revnumber><date>2015-11-02 15:39:14</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>65</revnumber><date>2015-08-20 14:48:06</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>64</revnumber><date>2015-04-27 16:02:32</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>63</revnumber><date>2015-04-27 16:02:18</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>62</revnumber><date>2015-01-27 16:56:46</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>61</revnumber><date>2014-11-10 12:17:38</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>60</revnumber><date>2013-03-08 10:17:16</date><authorinitials>localhost</authorinitials><revremark>converted to 1.6 markup</revremark></revision><revision><revnumber>59</revnumber><date>2012-08-23 12:34:57</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>58</revnumber><date>2012-06-26 14:39:15</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>57</revnumber><date>2012-06-26 14:38:58</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>56</revnumber><date>2012-01-05 15:28:48</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>55</revnumber><date>2011-07-27 14:28:05</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>54</revnumber><date>2011-07-27 14:02:47</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>53</revnumber><date>2011-03-21 12:29:27</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>52</revnumber><date>2011-03-21 11:42:06</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>51</revnumber><date>2011-03-21 11:41:50</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>50</revnumber><date>2010-07-22 12:44:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>49</revnumber><date>2010-07-22 12:41:53</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>48</revnumber><date>2010-07-22 12:09:33</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>47</revnumber><date>2010-07-22 10:08:25</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>46</revnumber><date>2010-07-02 11:14:56</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>45</revnumber><date>2010-04-15 14:33:28</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>44</revnumber><date>2010-01-28 15:55:09</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>43</revnumber><date>2010-01-19 12:43:28</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>42</revnumber><date>2010-01-19 12:42:57</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>41</revnumber><date>2010-01-11 16:57:56</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>40</revnumber><date>2010-01-11 16:53:56</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>39</revnumber><date>2009-11-13 11:30:50</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>38</revnumber><date>2009-11-11 12:15:43</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>37</revnumber><date>2009-11-11 12:15:30</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>36</revnumber><date>2009-11-03 16:07:05</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>35</revnumber><date>2009-11-03 15:31:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>34</revnumber><date>2008-04-28 15:07:44</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>33</revnumber><date>2008-04-24 15:49:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>32</revnumber><date>2008-04-24 15:47:52</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>31</revnumber><date>2008-04-24 15:35:49</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>30</revnumber><date>2008-04-23 09:27:02</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>29</revnumber><date>2008-04-23 09:15:02</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>28</revnumber><date>2008-02-11 16:39:15</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>27</revnumber><date>2008-02-11 16:35:53</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>26</revnumber><date>2007-10-18 13:13:15</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>25</revnumber><date>2007-10-15 10:33:27</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>24</revnumber><date>2007-08-13 15:37:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>23</revnumber><date>2007-08-09 15:11:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>22</revnumber><date>2007-08-09 13:46:43</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>21</revnumber><date>2007-08-09 13:18:39</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>20</revnumber><date>2007-07-17 14:40:13</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>19</revnumber><date>2007-07-13 11:01:26</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>18</revnumber><date>2007-04-04 14:45:04</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>17</revnumber><date>2007-04-04 14:37:37</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>16</revnumber><date>2007-04-04 14:33:21</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>15</revnumber><date>2007-04-04 14:32:35</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>14</revnumber><date>2007-03-16 11:15:34</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>13</revnumber><date>2007-03-16 10:58:59</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>12</revnumber><date>2007-03-02 11:30:40</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>11</revnumber><date>2007-03-02 11:28:01</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>10</revnumber><date>2007-02-01 16:22:21</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>9</revnumber><date>2007-01-05 10:15:30</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>8</revnumber><date>2006-12-15 17:18:10</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>7</revnumber><date>2006-12-15 17:17:31</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>6</revnumber><date>2006-12-15 17:14:30</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>5</revnumber><date>2006-12-15 17:12:53</date><authorinitials>IanNimmoSmith</authorinitials></revision><revision><revnumber>4</revnumber><date>2006-11-29 15:46:49</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>3</revnumber><date>2006-09-29 13:26:32</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>2</revnumber><date>2006-09-28 15:54:38</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>1</revnumber><date>2006-09-28 15:27:59</date><authorinitials>PeterWatson</authorinitials></revision></revhistory></articleinfo><section><title>Questions about p-values, significance or power of tests</title><orderedlist numeration="arabic"><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/pilot#">Can I combine pilot data with main study data?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/onesp#">When and how do I evaluate a one-sided p-value and quote a one-sided 95% confidence interval?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/powtabs#">What sample sizes do I need for doing tests with a given power?</ulink>  </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/effectSize#">A guide to magnitudes of effect sizes</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/prep#">Problems using p-rep, the Probability of Replication</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/dunlap#">A quick guide to choice of sample sizes for Cohen's effect sizes</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/comparezt#">A note on comparing z and t statistics and their p-values?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/td#">How do I convert a t-statistic (and an Odds Ratio) into an effect size?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/cd#">How do I compute Cohen's d in SPSS and EXCEL and its and eta-squared confidence interval in SPSS, R or EXCEL?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/hedgeg#">How do I compute Hedge's g from Cohen's d?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/mse#">How do I compute Mean Square Error (MSE) in EXCEL or SPSS?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/effcis#">A guide to obtaining confidence intervals for effect sizes</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/Escomp#">How do I compute effect sizes (including variance adjusted ones)?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/powprogs#">How do I do power calculations in SPSS, R, EXCEL and using web freeware?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/powposi#">How do I do power (sample size) calculations on Poisson counts?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/pownp#">How do I do power calculations using formulae for one sample t and sign tests?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/studyN#">General rules of thumb for sample sizes in pilot studies</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/powerFAQ?action=AttachFile&amp;do=get&amp;target=senspN.xls">How do I work out sample size for apriori specificities and sensitivities?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/equival#">How do I compute statistical tests of equivalence?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/SPSSpow#">Computing Power for ANOVAs using the SPSS GLM procedure</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/powerFAQ?action=AttachFile&amp;do=get&amp;target=MANpow.pdf">Computing Power for ANOVAs using the SPSS MANOVA procedure</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/FDR#">How do I do False Discovery Rate (FDR) corrections for multiple tests?</ulink>  </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/Bayes#">How do I calculate and interpret conditional probabilities?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/pvalsdef#">What is a p-value?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/pvalues#">How do I find p-values using critical values as input in SPSS and EXCEL?</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/pvs#">How do I adjust p-values for number of comparisons using SPSS and R?</ulink>  </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/SpssBonferroni#">Adjusted p-values</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/CombiningPvalues#">Combining p-values by Fisher's and Stouffer's methods</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/CombiningZandT#">Summing z values and summing t-values</ulink> </para></listitem><listitem><para><ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/powerFAQ/statswiki/FAQ/Fdfs#">Why does the value of one in the F distribution have a p-value which is less than 1?</ulink> </para></listitem></orderedlist></section></article>