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</o:shapelayout></xml><![endif]--></head><body lang=NL link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Dear Emanuel,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><p><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>I notice that there are many</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>different</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>views among scientists</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>about the use of one or two sided tests.<br>Most people say that you</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>always</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>have to test 2-sided.</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>But is there a rationale for this?</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>When is it appropriate and allowed to test one-sided?</span><span lang=EN> </span><o:p></o:p></p><p><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>Perhaps you can shed light on this topic, by giving your point of view</span><span lang=EN> </span><span lang=EN style='font-family:"Calibri","sans-serif";color:black'>or perhaps you can recommend literature that provides insight on this debate?</span><o:p></o:p></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'>If you have prior information that an effect will occur only on one side, or if you are only interested in an effect at one side, then you should test one-sided. Otherwise, you should test two-sided.<o:p></o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'>Eric<o:p></o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif"'>Thank you,</span><span lang=EN-US><o:p></o:p></span></p><p><span lang=EN-US style='font-family:"Calibri","sans-serif"'>Best Emanuel</span><o:p></o:p></p><p class=MsoNormal><br clear=all><o:p></o:p></p><p><span style='font-size:8.0pt;font-family:"Arial","sans-serif"'>Het UMC St Radboud staat geregistreerd bij de Kamer van Koophandel in het handelsregister onder nummer 41055629.<br>The Radboud University Nijmegen Medical Centre is listed in the Commercial Register of the Chamber of Commerce under file number 41055629.<o:p></o:p></span></p></div></div></body></html>