Description Usage Format Details Source References See Also Examples
Data on seizure counts for 59 epileptics.
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A data frame with 236 observations on the following 6 variables.
id
a numeric vector, identification number for each patient
count
a numeric vector, seizure counts
visit
a numeric vector, visit number
trx
a numeric vector, treatment: progabide (1) or placebo (0)
baseline
a numeric vector, baseline 8 week seizure count
age
a numeric vector, age of patient
The data are from a placebo-controlled clinical trial of 59 epileptics. Patients with partial seizures were enrolled in a randomized clinical trial of the anti-epileptic drug, progabide. Participants in the study were randomized to either progabide or a placebo, as an adjuvant to the standard anti-epileptic chemotherapy. Progabide is an anti-epileptic drug whose primary mechanism of action is to enhance gamma-aminobutyric acid (GABA) content; GABA is the primary inhibitory neurotransmitter in the brain. Prior to receiving treatment, baseline data on the number of epileptic seizures during the preceding 8-week interval were recorded. Counts of epileptic seizures during 2-week intervals before each of four successive post-randomization clinic visits were recorded.
P.F Thall, and S.C. Vail (1990). Some covariance models for longitudinal count data with overdispersion. Biometrics, 46, 657-671,
P. Hougaard, M.L. Ting Lee, and G.A. Whitmore (1997): Analysis of overdispersed count data by mixtures of poisson variables and poisson processes. Biometrics 53, pages 1225-1238.
testPoissonTweedie
mlePoissonTweedie
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | # Although this is not a differential expression dataset, it is appropriate
# to illustrate the application of the Poisson-Tweedie in
# epidemiological studies
data(seizure)
summary(seizure)
# Aggregate
aggCounts <- aggregate(x = cbind(seizure$count, seizure$trx), by =
list(seizure$id), FUN = sum)
# Estimation of the three parameters for all individuals
mleSeizure <- mlePoissonTweedie(x = aggCounts[,2], a.ini = 0, D.ini = 10)
mleSeizure
#Poisson-Tweedie test
testPoissonTweedie(x = aggCounts[,2], group = aggCounts[,3])
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