Obtains the error spent at given spending times
for the specified error spending function.
Usage
errorSpent(t, error, sf = "sfOF", sfpar = NA)
Value
A vector of errors spent up to the interim look.
Arguments
t
A vector of spending times, typically equal to information
fractions.
error
The total error to spend.
sf
The spending function. One of the following: "sfOF" for
O'Brien-Fleming type spending function, "sfP" for Pocock type spending
function, "sfKD" for Kim & DeMets spending function, and "sfHSD" for
Hwang, Shi & DeCani spending function. Defaults to "sfOF".
sfpar
The parameter for the spending function. Corresponds to
rho for "sfKD" and gamma for "sfHSD".