simData1s: Simulate faecal egg count data (1-sample situation)

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/simData.R

Description

Simulates (zero-inflated) egg count data

Usage

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simData1s(n = 10, mean = 500, kappa = 0.5, phi = 1, 
  f = 50, rounding = TRUE, seed = NULL)

Arguments

n

sample size (number of faeces collected)

mean

true number of eggs per gram (epg)

kappa

overdispersion parameter, κ -> ∞ corresponds to Poisson distribution

phi

prevalence, i.e. proportion of infected animals, between 0 and 1

f

correction factor of the egg counting technique, either an integer or a vector of integers with length n

rounding

logical. If TRUE, the Poisson mean for the raw counts is rounded. The rounding applies since the mean epg is frequently reported as an integer value. For more information, please see Details.

seed

an integer that will be used in a call to set.seed before simulation. If NULL, a random seed is allocated.

Details

In the simulation of raw (master) counts, it follows a Poisson distribution with some mean. The mean is frequently rounded down if it has a very low value and rounding = TRUE, hence there expects to be a negative bias overall when μ < 150. Set rounding = FALSE if one does not wish to have any bias in the simulated counts.

Value

A data.frame with three columns, namely the observed epg (obs), number of eggs counted on microscope slide (master) and true epg in the sample(true).

Author(s)

Craig Wang
Michaela Paul

See Also

fec_stan for analyzing faecal egg count data with one sample

Examples

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fec <- simData1s(n=10, mean=500, kappa=0.5, phi=0.7)

eggCounts documentation built on May 2, 2018, 5:06 p.m.