R: Examples for 'stats::power.prop.test'

### ** Examples

power.prop.test(n = 50, p1 = .50, p2 = .75)      ## => power = 0.740

     Two-sample comparison of proportions power calculation 

              n = 50
             p1 = 0.5
             p2 = 0.75
      sig.level = 0.05
          power = 0.7401659
    alternative = two.sided

NOTE: n is number in *each* group

power.prop.test(p1 = .50, p2 = .75, power = .90) ## =>     n = 76.7

     Two-sample comparison of proportions power calculation 

              n = 76.70693
             p1 = 0.5
             p2 = 0.75
      sig.level = 0.05
          power = 0.9
    alternative = two.sided

NOTE: n is number in *each* group

power.prop.test(n = 50, p1 = .5, power = .90)    ## =>    p2 = 0.8026

     Two-sample comparison of proportions power calculation 

              n = 50
             p1 = 0.5
             p2 = 0.8026141
      sig.level = 0.05
          power = 0.9
    alternative = two.sided

NOTE: n is number in *each* group

power.prop.test(n = 50, p1 = .5, p2 = 0.9, power = .90, sig.level=NULL)

     Two-sample comparison of proportions power calculation 

              n = 50
             p1 = 0.5
             p2 = 0.9
      sig.level = 0.001318068
          power = 0.9
    alternative = two.sided

NOTE: n is number in *each* group

                                                 ## => sig.l = 0.00131
power.prop.test(p1 = .5, p2 = 0.501, sig.level=.001, power=0.90)

     Two-sample comparison of proportions power calculation 

              n = 10451937
             p1 = 0.5
             p2 = 0.501
      sig.level = 0.001
          power = 0.9
    alternative = two.sided

NOTE: n is number in *each* group

                                                 ## => n = 10451937
try(
 power.prop.test(n=30, p1=0.90, p2=NULL, power=0.8)
) # a warning  (which may become an error)

Warning in power.prop.test(n = 30, p1 = 0.9, p2 = NULL, power = 0.8): No p2 in
[p1, 1] can be found to achieve the desired power

     Two-sample comparison of proportions power calculation 

              n = 30
             p1 = 0.9
             p2 = 1.030182
      sig.level = 0.05
          power = 0.8
    alternative = two.sided

NOTE: n is number in *each* group

## Reason:
power.prop.test(      p1=0.90, p2= 1.0, power=0.8) ##-> n = 73.37

     Two-sample comparison of proportions power calculation 

              n = 73.37427
             p1 = 0.9
             p2 = 1
      sig.level = 0.05
          power = 0.8
    alternative = two.sided

NOTE: n is number in *each* group

Examples for 'stats::power.prop.test'

Power Calculations for Two-Sample Test for Proportions