AudreyM Tracker
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AudreyM TrackerMon, 15 Jul 2024 18:30:59 GMT2024-07-15T18:30:59ZProc Freq Exact binomial Test p-value
https://communities.sas.com/t5/Statistical-Procedures/Proc-Freq-Exact-binomial-Test-p-value/m-p/893703#M44280
<P>when i do the Exact Binomial Test with PROC FREQ (H0: P<=P0, H1: P>P0), i can obtain the p-value as:</P><P>One-sided Pr <= P</P><P>or</P><P>One-sided Pr >= P </P><P>depending on the Z statistics value.</P><P> </P><P>having doing some checks with other softwares, i need to use One-sided Pr >= P but One-sided Pr >= P is not equal to 1 - One-sided Pr <= P because the part of the "=" is included in both p-values.</P><P>1) So is there a way to force SAS to always present the p-value in the same way (i.e. always One-sided Pr >= P for example)?</P><P>2) if you are interested by "One-sided Pr >= P", how do you manage to have the correct p-value because when i have the p-value "One-sided Pr <= P", i cannot simply do "1-One-sided Pr <= P".</P><P> </P><P>Thanks.</P>Tue, 12 Sep 2023 06:27:30 GMThttps://communities.sas.com/t5/Statistical-Procedures/Proc-Freq-Exact-binomial-Test-p-value/m-p/893703#M44280AudreyM2023-09-12T06:27:30ZConditional power calculation for the difference of proportions
https://communities.sas.com/t5/Statistical-Procedures/Conditional-power-calculation-for-the-difference-of-proportions/m-p/857079#M42456
<P>Hello,</P><P> </P><P>i need to perform a futility analysis where the hypothesis of testing are:</P><P>The null hypothesis H0: Rc-Ra ≤ -10</P><P>The alternative hypothesis H1: Rc-Ra > -10</P><P>where Rc and Ra are the response rate of treatments C and A respectively.</P><P> </P><P>At the end of the study Nc = 450, Na = 300 subjects.</P><P>where Nc and Na are the number of subjects planned to be randomised in treatments C and A respectively.</P><P> </P><P>At futility analysis time, i have Nc = 215, Na = 143 subjects and Rc=0.703 and Ra=0.618</P><P> </P><P>i need to calculate the conditional power at time of futility analysis.</P><P>i looked into SAS support but i am not really clear what procedure is the most appropriate and the SAS codes/options.</P><P> </P><P>thanks for your help.</P>Fri, 03 Feb 2023 16:55:32 GMThttps://communities.sas.com/t5/Statistical-Procedures/Conditional-power-calculation-for-the-difference-of-proportions/m-p/857079#M42456AudreyM2023-02-03T16:55:32ZPROC GENMOD
https://communities.sas.com/t5/Statistical-Procedures/PROC-GENMOD/m-p/850380#M42103
<P>When i run my Proc Genmod, i have the message "ERROR: Floating Point Zero Divide". </P><P> </P><P><SPAN>PROC GENMOD DATA = _1;</SPAN><BR /><SPAN> CLASS TRTP1-TRTP3 country1-country21 NEXTGR11-NEXTGR12 FEVPGR11-FEVPGR13;</SPAN><BR /><SPAN> MODEL AVAL = TRTP1-TRTP3 country1-country21 NEXTGR11-NEXTGR12 FEVPGR11-FEVPGR13 /</SPAN><BR /><SPAN> OFFSET=LNFUDUR2 DIST=negbin LINK=log;</SPAN><BR /><SPAN> BAYES SEED=22022021 COEFFPRIOR=uniform THIN=100 OUTPOST= dataset2 NMC=100000;</SPAN><BR /><SPAN>RUN;</SPAN></P><P> </P><P><SPAN>i am trying to find solutions and i have seen that if i modify AVAL values by AVAL+1 then the model runs (it means that instead of having a range of values between 0 and 5, it is now between 1 and 6).</SPAN></P><P> </P><P><SPAN>Is that an acceptable solution (i have tried and a small number of data and i have a slight variation of results)?</SPAN></P><P> </P><P><SPAN>Thanks</SPAN></P>Mon, 19 Dec 2022 20:28:02 GMThttps://communities.sas.com/t5/Statistical-Procedures/PROC-GENMOD/m-p/850380#M42103AudreyM2022-12-19T20:28:02ZERROR: Floating Point Zero Divide PROC GENMOD
https://communities.sas.com/t5/SAS-Studio/ERROR-Floating-Point-Zero-Divide-PROC-GENMOD/m-p/850336#M10724
<P>i have to do this proc genmod:</P><P>PROC GENMOD DATA = _1;<BR /> CLASS TRTP1-TRTP3 country1-country21 NEXTGR11-NEXTGR12 FEVPGR11-FEVPGR13;<BR /> MODEL AVAL = TRTP1-TRTP3 country1-country21 NEXTGR11-NEXTGR12 FEVPGR11-FEVPGR13 /<BR /> OFFSET=LNFUDUR2 DIST=negbin LINK=log;<BR /> BAYES SEED=22022021 COEFFPRIOR=uniform THIN=100 OUTPOST= dataset2 NMC=100000;<BR />RUN;</P><P> </P><P>but unfortunately, i have the below error messages (all the covariates are binary 0/1 and the AVAL variable includes only integer values from 0 to 5. Only the OFFSET variable is a continuous variable)</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="AudreyM_0-1671449940332.png" style="width: 400px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/78710iAEF7A996A1EBD54E/image-size/medium?v=v2&px=400" role="button" title="AudreyM_0-1671449940332.png" alt="AudreyM_0-1671449940332.png" /></span></P><P> </P><P>The distribution of AVAL is the following:</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="AudreyM_1-1671450115242.png" style="width: 400px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/78711iFDC7D11B844BA96F/image-size/medium?v=v2&px=400" role="button" title="AudreyM_1-1671450115242.png" alt="AudreyM_1-1671450115242.png" /></span></P><P> </P><P>my thought is that is due to the low variability of AVAL because in a lot of strata, the available values of AVAL are only 0.</P><P> </P><P>But these are the data that i have so i cannot change them. i have tried to round the offset variable so have a fix number of digits but does not change the outcome.</P><P> </P><P>Would you have any solution to resolve this?</P><P> </P><P>Thanks</P><P>Audrey</P><P> </P><P> </P>Mon, 19 Dec 2022 11:43:58 GMThttps://communities.sas.com/t5/SAS-Studio/ERROR-Floating-Point-Zero-Divide-PROC-GENMOD/m-p/850336#M10724AudreyM2022-12-19T11:43:58Z