The PAIREDFREQ statement performs power and sample size analyses for McNemar’s test for paired proportions.
Table 77.14 summarizes the options available in the PAIREDFREQ statement.
Table 77.14: PAIREDFREQ Statement Options
Option |
Description |
---|---|
Define analysis |
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Specifies the underlying distribution assumed for the test statistic |
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Specifies the statistical analysis |
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Specify analysis information |
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Specifies the significance level |
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Specifies the null value of the ratio of discordant proportions |
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Specifies the number of sides and the direction of the statistical test or confidence interval |
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Specify effects |
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Specifies the correlation between members of a pair |
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Specifies the discordant proportion difference |
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Specifies the two discordant proportions, and |
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Specifies the ratio |
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Specifies the odds ratio |
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Specifies the two paired proportions, and |
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Specifies the proportion difference |
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Specifies either the reference first proportion or the reference discordant proportion |
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Specifies the relative risk |
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Specifies the discordant proportion sum, |
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Specify sample size |
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Enables fractional input and output for sample sizes |
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Specifies the total number of proportion pairs |
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Specify power |
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Specifies the desired power of the test |
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Choose computational method |
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Specifies the computational method |
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Control ordering in output |
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Controls the output order of parameters |
Table 77.15 summarizes the valid result parameters in the PAIREDFREQ statement.
To specify the proportions, choose one of the following parameterizations:
discordant proportions (using the DISCPROPORTIONS= option)
difference and sum of discordant proportions (using the DISCPROPDIFF= and TOTALPROPDISC= options)
difference of discordant proportions and reference discordant proportion (using the DISCPROPDIFF= and REFPROPORTION= options)
ratio of discordant proportions and reference discordant proportion (using the DISCPROPRATIO= and REFPROPORTION= options)
ratio and sum of discordant proportions (using the DISCPROPRATIO= and TOTALPROPDISC= options)
paired proportions and correlation (using the PAIREDPROPORTIONS= and CORR= options)
proportion difference, reference proportion, and correlation (using the PROPORTIONDIFF= , REFPROPORTION= , and CORR= options)
odds ratio, reference proportion, and correlation (using the ODDSRATIO= , REFPROPORTION= , and CORR= options)
relative risk, reference proportion, and correlation (using the RELATIVERISK= , REFPROPORTION= , and CORR= options)
This section summarizes the syntax for the common analyses supported in the PAIREDFREQ statement.
You can express effects in terms of the individual discordant proportions, as in the following statements. Default values for the TEST= , SIDES= , ALPHA= , and NULLDISCPROPRATIO= options specify a two-sided McNemar test for no effect with a significance level of 0.05.
proc power; pairedfreq dist=exact_cond discproportions = 0.15 | 0.45 npairs = 80 power = .; run;
You can also express effects in terms of the difference and sum of discordant proportions:
proc power; pairedfreq dist=exact_cond discpropdiff = 0.3 totalpropdisc = 0.6 npairs = 80 power = .; run;
You can also express effects in terms of the difference of discordant proportions and the reference discordant proportion:
proc power; pairedfreq dist=exact_cond discpropdiff = 0.3 refproportion = 0.15 npairs = 80 power = .; run;
You can also express effects in terms of the ratio of discordant proportions and the denominator of the ratio:
proc power; pairedfreq dist=exact_cond discpropratio = 3 refproportion = 0.15 npairs = 80 power = .; run;
You can also express effects in terms of the ratio and sum of discordant proportions:
proc power; pairedfreq dist=exact_cond discpropratio = 3 totalpropdisc = 0.6 npairs = 80 power = .; run;
You can also express effects in terms of the paired proportions and correlation:
proc power; pairedfreq dist=exact_cond pairedproportions = 0.6 | 0.8 corr = 0.4 npairs = 45 power = .; run;
You can also express effects in terms of the proportion difference, reference proportion, and correlation:
proc power; pairedfreq dist=exact_cond proportiondiff = 0.2 refproportion = 0.6 corr = 0.4 npairs = 45 power = .; run;
You can also express effects in terms of the odds ratio, reference proportion, and correlation:
proc power; pairedfreq dist=exact_cond oddsratio = 2.66667 refproportion = 0.6 corr = 0.4 npairs = 45 power = .; run;
You can also express effects in terms of the relative risk, reference proportion, and correlation:
proc power; pairedfreq dist=exact_cond relativerisk = 1.33333 refproportion = 0.6 corr = 0.4 npairs = 45 power = .; run;
The following statements demonstrate a sample size computation for the normal-approximate McNemar test. The default value for the METHOD= option specifies an exact sample size computation. Default values for the TEST= , SIDES= , ALPHA= , and NULLDISCPROPRATIO= options specify a two-sided McNemar test for no effect with a significance level of 0.05.
proc power; pairedfreq dist=normal method=connor discproportions = 0.15 | 0.45 npairs = . power = .9; run;