Calculate power or sample size for any 2x2 test.
The function Power2x2 and SS2x2 calculates the power or sample size for any 2x2 test, while the function uncondPower2x2 calculates power for only tests supported by
uncondExact2x2Pvals.
Power2x2(n1, n2, theta1, theta2, alpha, pvalFunc, ...) uncondPower2x2(n1,n2, theta1, theta2, alpha, ...) SS2x2(theta1, theta2, alpha, pvalFunc, power=0.90, n1start=10, increaseby=1, n2.over.n1=1, maxiter=50, printSteps=TRUE, ...)
n1 |
sample size in group 1 |
n2 |
sample size in group 2 |
theta1 |
probability of success in group 1 |
theta2 |
probability of success in group 2 |
alpha |
significance level |
pvalFunc |
function that inputs x1,n1,x2,n2 and outputs a p-value. |
power |
target power |
n1start |
value of n1 for first iteration |
increaseby |
positive integer, how much to increase n1 by for each iteration |
n2.over.n1 |
ratio of n2/n1 |
maxiter |
maximum number of iterations |
printSteps |
logical, should the power and sample size be printed after each iteration? |
... |
arguments passed to |
The function Power2x2 is a very simple function
to calculate power. It calculates power where rejection is when the p-value from pvalFunc is less than or equal to alpha. The function SS2x2 repeatedly calls Power2x2 as it increases the sample size, stopping when
the power is greater than 'power'.
The function uncondPower2x2 is similar except the
p-values are calculated by uncondExact2x2Pvals.
the power functions return only the power. The sample size function returns a list of class 'htest.power'.
library(exact2x2)
Power2x2(3,4,.1,.9,0.025, pvalFunc=
function(x1,n1,x2,n2){
boschloo(x1,n1,x2,n2, alternative="greater",
or=1,tsmethod="central", midp=TRUE)$p.value
}
)
##
## Not run:
SS2x2(.1,.9,0.025, n1start=5, pvalFunc=
function(x1,n1,x2,n2){
boschloo(x1,n1,x2,n2, alternative="greater",
or=1,tsmethod="central", midp=TRUE)$p.value
}
)
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.