SimDesign (version 1.13)

Generate: Generate data

Description

Generate data from a single row in the design input (see runSimulation). R contains numerous approaches to generate data, some of which are contained in the base package, as well as in SimDesign (e.g., rmgh, rValeMaurelli, rHeadrick). However the majority can be found in external packages. See CRAN's list of possible distributions here: https://CRAN.R-project.org/view=Distributions. Note that this function technically can be omitted if the data generation is provided in the Analyse step, though in general this is not recommended.

Usage

Generate(condition, fixed_objects = NULL)

Arguments

condition

a single row from the design input (as a data.frame), indicating the simulation conditions

fixed_objects

object passed down from runSimulation

Value

returns a single object containing the data to be analyzed (usually a vector, matrix, or data.frame), or list

References

Sigal, M. J., & Chalmers, R. P. (2016). Play it again: Teaching statistics with Monte Carlo simulation. Journal of Statistics Education, 24(3), 136-156. 10.1080/10691898.2016.1246953

See Also

add_missing, Attach, rmgh, rValeMaurelli, rHeadrick

Examples

# NOT RUN {
mygenerate <- function(condition, fixed_objects = NULL){
    N1 <- condition$sample_sizes_group1
    N2 <- condition$sample_sizes_group2
    sd <- condition$standard_deviations

    group1 <- rnorm(N1)
    group2 <- rnorm(N2, sd=sd)
    dat <- data.frame(group = c(rep('g1', N1), rep('g2', N2)),
                      DV = c(group1, group2))
    # just a silly example of a simulated parameter
    pars <- list(random_number = rnorm(1))

    list(dat=dat, parameters=pars)
}

# similar to above, but using the Attach() function instead of indexing
mygenerate <- function(condition, fixed_objects = NULL){
    Attach(condition)
    N1 <- sample_sizes_group1
    N2 <- sample_sizes_group2
    sd <- standard_deviations

    group1 <- rnorm(N1)
    group2 <- rnorm(N2, sd=sd)
    dat <- data.frame(group = c(rep('g1', N1), rep('g2', N2)),
                      DV = c(group1, group2))
    dat
}

mygenerate2 <- function(condition, fixed_objects = NULL){
    mu <- sample(c(-1,0,1), 1)
    dat <- rnorm(100, mu)
    dat        #return simple vector (discard mu information)
}

mygenerate3 <- function(condition, fixed_objects = NULL){
    mu <- sample(c(-1,0,1), 1)
    dat <- data.frame(DV = rnorm(100, mu))
    dat
}

# }
# NOT RUN {
# }