M = 10000 # Number of sims | |
power = .5 # power | |
## Binomial (fixed N) | |
N1 = rpois(M,2) + 1 ## random choice for N | |
X1 = rbinom(M,N1,power) ## Perform studies | |
mean(X1 / N1) | |
sd(X1 / N1) | |
## Notice above that, as expected, expected prop. | |
## of significant studies is power | |
## Geometric (stop with single nonsig. result) | |
X2 = rgeom(M,1-power) | |
N2 = X2 + 1 | |
# show power | |
sum(X2) / sum(N2) | |
# However, expected proportion sig. is < .5 ! | |
mean(X2 / N2) | |
sd(X2 / N2) | |
## Interestingly, the expected proportion of sig. | |
## studies is *less than* the power! |
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