Description Usage Format References
Thall and Vail (1990) presented longitudinal data from a clinical trial of 59 epileptics, who were randomized to a new drug or a placebo (T=0 or T=1). Baseline data were available at the start of the trial; the trial included the logarithm of the average number of epileptic seizures recorded in the 8-week period preceding the trial (B), the logarithm of age (A), and visit (V: a linear trend, coded (-3,-1,1,3)/10). A multivariate response variable (y) consists of the seizure counts during 2-week periods before each of four visits to the clinic.
1 | data("epilepsy")
|
A data frame with 236 observations on the following 7 variables.
yseizure counts during 2-week periods before each of four visits to the clinic
Ttreatment (0=new drug, 1=placebo)
Baverage number of epileptic seizures in the 8-week period preceding the trial
Alogarithm of age (in years) of each patient
Vlinear trend coded (-3, -1, 1, 3)/10 for four visits of each patient
patientpatient number for 59 epileptics
idobservation number for 236 observations
Thall, P.F. and Vail, S.C. (1990). Some covariance models for longitudinal count data with overdispersion, Biometrics, 46, 657–671.
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