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Simulating ED values under various scenarios

Source: R/simDR.R
simDR.Rd

Simulating ED values for a given model and given dose values.

Usage

simDR(
  mpar,
  sigma,
  fct,
  noSim = 1000,
  conc,
  edVec = c(10, 50),
  seedVal = 20070723
)

Arguments

mpar

numeric vector of model parameters.

sigma

numeric specifying the residual standard deviation.

fct

list supplying the chosen dose-response mean function (e.g., LL.4()).

noSim

numeric giving the number of simulations. Defaults to 1000.

conc

numeric vector of concentration/dose values. Must contain at least 5 values.

edVec

numeric vector of ED levels to estimate in each simulation. Defaults to c(10, 50).

seedVal

numeric giving the seed used to initialise the random number generator. Defaults to 20070723.

Value

Invisibly returns a list with one element:

se

A 3D array of dimensions (length(conc) - 4) x 6 x length(edVec) containing empirical standard deviations of the estimated ED values. Rows correspond to the number of concentration levels used (starting from 5). Columns correspond to the number of replicates per concentration (1 to 6). The third dimension corresponds to each ED level in edVec.

The array values are also printed to the console during execution.

Details

The arguments mpar and sigma are typically obtained from a previous model fit. Only dose-response models assuming normally distributed errors can be used.

Author

Christian Ritz, Hannes Reinwald

Examples

ryegrass.m1 <- drm(ryegrass, fct = LL.4())

simDR(
  mpar     = coef(ryegrass.m1),
  sigma    = sqrt(summary(ryegrass.m1)$resVar),
  fct      = LL.4(),
  noSim    = 2,
  conc     = c(1.88, 3.75, 7.50, 0.94, 15, 0.47, 30, 0.23, 60),
  seedVal  = 20070723
)
#> Concentrations used: 1.88 3.75 7.5 0.94 15 0.47 30 0.23 60 
#> 
#> ED value considered: 10 
#> Conc. no.\Replicates: 
#>           1          2         3          4         5          6
#> 5 1.7937943 0.70676461 0.7070331 0.74477323 0.0314240 0.47265995
#> 6 0.7715370 0.07489298 0.1991687 0.50345455 0.0274019 0.26133303
#> 7 0.6766681 0.43816932 0.3241948 0.57191204 0.4956274 0.02968537
#> 8 0.5276024 0.20800084 0.2113615 0.05549555 0.2561400 0.28737212
#> 9 0.1800602 0.76739811 0.5514185 0.11201042 0.4834278 0.46828149
#> 
#> 
#> ED value considered: 50 
#> Conc. no.\Replicates: 
#>           1          2          3         4         5         6
#> 5 0.6998346 1.32865730 0.49266733 0.4490645 0.1069289 0.6018208
#> 6 6.7983515 0.39097416 0.09645987 0.5823232 0.4309704 0.4252761
#> 7 0.9155897 0.03037852 0.46647071 0.2017280 0.3129933 0.3744331
#> 8 0.3950825 0.16439311 0.21879117 0.0803034 0.2577441 0.2953281
#> 9 0.3519176 1.19098825 0.34427430 0.1302080 0.4812865 0.2009490
#> 
#>