simulate.safeDesign: Simulate Early Stopping Experiments for the T Test
In safestats: Safe Anytime-Valid Inference

simulate.safeDesign

R Documentation

Simulate Early Stopping Experiments for the T Test

Description

Applied to a 'safeDesign' object this function empirically shows the performance of safe experiments under optional stopping.

Usage

## S3 method for class 'safeDesign'
simulate(
  object,
  nsim = nSim,
  seed = NULL,
  deltaTrue = NULL,
  muGlobal = 0,
  sigmaTrue = 1,
  lowN = 3,
  safeOptioStop = TRUE,
  freqOptioStop = FALSE,
  nPlanFreq = NULL,
  logging = TRUE,
  pb = TRUE,
  nSim = 1,
  ...
)

Arguments

`object`	A safeDesign obtained obtained from `designSafeT()`.
`nsim`	integer, formally the number of iterations, but by default nsim=nSim
`seed`	integer, seed number.
`deltaTrue`	numeric, if NULL, then the minimally clinically relevant standardised effect size is used as the true data generating effect size deltaTrue.
`muGlobal`	numeric, the true global mean of a paired or two-sample t-test. Its value should not matter for the test. This parameter is treated as a nuisance.
`sigmaTrue`	numeric > 0,the true standard deviation of the data. Its value should not matter for the test.This parameter treated is treated as a nuisance.
`lowN`	integer that defines the smallest n of our search space for n.
`safeOptioStop`	logical, `TRUE` implies that optional stopping simulation is performed for the safe test.
`freqOptioStop`	logical, `TRUE` implies that optional stopping simulation is performed for the frequentist test.
`nPlanFreq`	the frequentist sample size(s) to plan for. Acquired from `designFreqT()`.
`logging`	logical, if `TRUE`, then return the simulated data.
`pb`	logical, if `TRUE`, then show progress bar.
`nSim`	integer, number of iterations.
`...`	further arguments to be passed to or from methods.

Value

Returns an object of class "safeTSim". An object of class "safeTSim" is a list containing at least the following components:

nPlan: the planned sample size(s).
deltaTrue: the value of the true standardised effect size (test-relevant parameter) provided by the user.
muGlobal: the true global mean of a paired or two-sample t-test (nuisance parameter) provided by the user.
paired: if TRUE then paired t-test.
alternative: any of "twoSided", "greater", "less" provided by the user.
lowN: the smallest number of samples (first group) at which monitoring of the tests begins.
nSim: the number of replications of the experiment.
alpha: the tolerable type I error provided by the user.
beta: the tolerable type II error provided by the user.
testType: any of "oneSample", "paired", "twoSample" provided by the user.
parameter: the parameter (point prior) used in the safe test derived from the design. Acquired from designSafeT().
nPlanFreq: the frequentist planned sample size(s). Acquired from designFreqT()
safeSim: list with the simulation results of the safe test under optional stopping.
freqSim: list with the simulation results of the frequentist test under optional stopping.

Examples

# Design safe test
alpha <- 0.05
beta <- 0.20
deltaMin <- 1
designObj <- designSafeT(deltaMin, alpha=alpha, beta=beta, nSim=100)

# Design frequentist test
freqObj <- designFreqT(deltaMin, alpha=alpha, beta=beta)

# Simulate based on deltaTrue=deltaMin
simResultsDeltaTrueIsDeltaMin <- simulate(object=designObj, nSim=100)

# Simulate based on deltaTrue > deltaMin
simResultsDeltaTrueIsLargerThanDeltaMin <- simulate(
  object=designObj, nSim=100, deltaTrue=2)

# Simulate under the null deltaTrue = 0
simResultsDeltaTrueIsNull <- simulate(
  object=designObj, nSim=100, deltaTrue=0)

simulate(object=designObj, deltraTrue=0, nSim=100, freqOptioStop=TRUE,
         nPlanFreq=freqObj$nPlan)

safestats documentation built on Nov. 24, 2022, 5:07 p.m.