exams.forge (version 1.0.10)

ttests: T-tests

Description

ttests runs a variety of modifications to the input parameters of ttest, in order to generate all possible t-tests. See under "Details" the detailed parameter values which are used. Note that not giving the parameter hyperloop will results in approx. 5000 t-tests generated. Returned will be only the different t-tests with the first element being ttest. If only a specific element of a ttest is of interest then just give the name of the element in elem and then all ttests will be returned where elem is different.

Usage

ttests(ttest, elem = NULL, hyperloop = NULL)

Value

A list of ttest objects is returned

Arguments

ttest

ttest: the base result from a valid t-test generated by ttest_num()

elem

character: element to extract (default: NULL)

hyperloop

named list: parameter values to run over (default: see above)

Details

The default hyperloop is:

list(n           = c(1, ttest$n, ttest$n+1),
     mu0         = c(ttest$mu0, ttest$mean),
     mean        = c(ttest$mu0, ttest$mean), 
     sigma       = c(ttest$sigma, ttest$sd, sqrt(ttest$sigma), sqrt(ttest$sd)),
     sd          = c(ttest$sigma, ttest$sd, sqrt(ttest$sigma), sqrt(ttest$sd)),
     norm        = c(TRUE, FALSE),
     alpha       = unique(c(ttest$alpha, 0.01, 0.05, 0.1)),
     alternative = c("two.sided", "greater", "less")
    )

Examples

basetest  <- ttest_num(mean=0.5, sd=1.25, n=50, sigma=1)
# vary the number of observations
hyperloop <- list(n=c(1, basetest$n, basetest$n^2))
# return all different t-tests
tts       <- ttests(basetest, hyperloop=hyperloop)
# return all different random sampling functions
ttests(basetest, "Xbar", hyperloop)