https://communities.sas.com/t5/Statistical-Procedures/proc-power-TwoSampleFreq-How-to-write-for-a-lower-sided-test/m-p/298462#M15885 <P>&nbsp;A proportion is a number 0 &lt; p &lt; 1. Try</P> <P>groupproportions = (0.15 0.05)</P> <P>&nbsp;</P> Wed, 14 Sep 2016 23:30:43 GMT Rick_SAS 2016-09-14T23:30:43Z https://communities.sas.com/t5/Statistical-Procedures/proc-power-TwoSampleFreq-How-to-write-for-a-lower-sided-test/m-p/298438#M15884 <P>&nbsp;</P> <P>&nbsp;</P> <P>I’m trying to calculate minimum sample sizes for a A/B hypothesis test .&nbsp;&nbsp; I hypothesizing a 10% decrease based on a historical benchmark of 5%.&nbsp; How to you write the syntax for this.&nbsp; The below is not correct. &nbsp;Sides=L makes sense to me but in the&nbsp;<SPAN>GroupProportions = ( 0.05 -0.05) the <STRONG>-0.50 </STRONG>is is casuing an error.&nbsp;</SPAN></P> <P>&nbsp;</P> <P>Any assistance will be greatly appreciated!&nbsp;</P> <P>&nbsp;</P> <P>proc power;<BR /> TwoSampleFreq<BR /> Test=Fisher<BR /> Alpha = 0.01<BR /> Sides = <STRONG>L</STRONG><BR /> GroupProportions = ( 0.05<STRONG> -0.05</STRONG>)<BR /> Power =.8<BR /> Npergroup =.;run;</P> Wed, 14 Sep 2016 20:33:54 GMT https://communities.sas.com/t5/Statistical-Procedures/proc-power-TwoSampleFreq-How-to-write-for-a-lower-sided-test/m-p/298438#M15884 Mgarret 2016-09-14T20:33:54Z https://communities.sas.com/t5/Statistical-Procedures/proc-power-TwoSampleFreq-How-to-write-for-a-lower-sided-test/m-p/298462#M15885 <P>&nbsp;A proportion is a number 0 &lt; p &lt; 1. Try</P> <P>groupproportions = (0.15 0.05)</P> <P>&nbsp;</P> Wed, 14 Sep 2016 23:30:43 GMT https://communities.sas.com/t5/Statistical-Procedures/proc-power-TwoSampleFreq-How-to-write-for-a-lower-sided-test/m-p/298462#M15885 Rick_SAS 2016-09-14T23:30:43Z