Abundance of trichostrongyloid eggs in sheep faeces

Description

This data set contains information about the abundance and distribution of trichostrongyloid eggs in the faeces of 14 groups of commercially farmed sheep given in Table 1 in Morgan et al. (2005). The faecal egg counts were assumed to follow a negative binomial distribution with mean m and overdispersion parameter k.

Usage

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data(tab1morgan)

Format

A data frame with 14 rows and 13 variables

Details

The data set has columns:

group ID number for the groups
ageclass age class of sheep: "Lambs" or "Ewes"
month month when samples were taken
n number of sheep in group
meanFEC mean number of eggs per gram (epg) of faeces
k estimated overdispersion parameter k
k.low lower limit of a 95% confidence interval for k
k.up lower limit of a 95% confidence interval for k
maxFEC maximal number of eggs per gram of faeces per group
percentageLarger1000 percentage of samples with more than 1000 epg
Chi2 goodness-of-fit statistic for the negative binomial distribution
df corresponding degrees of freedom
p corresponding p-value

Source

Morgan ER, Cavill L, Curry GE, Wood RM, Mitchell ESE (2005). Effects of aggregation and sample size on composite faecal egg counts in sheep, Veterinary Parasitology, 121:79-87.

Examples

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data(tab1morgan)
if (require("lattice"))
   xyplot(k.low+k.up+k ~meanFEC, type="p", pch=19, col=c(8,8,1), data=tab1morgan)