dental {hassediagrams} | R Documentation |
A crossover design for a dental study
Description
This is a crossover design (Study H) given in Newcombe et al. (1995) to study the effects of CHX rinses on 4 day plaque regrowth. The study consisted of 24 patients assessed over 3 treatment periods. The purpose of the study was to compare 2 CHX rinses with saline. The design is based on pairs of Latin squares balanced for carry over.
Usage
data(dental)
Format
A crossover design of 72 runs on 5 variables/factors. The 5 variables/factors included in the design are:
- Sequence
Categoric factor with levels 1-6.
- Subject
Categoric factor with levels 1-32.
- Period
Categoric factor with levels 1-3.
- Treatment
Categoric factor with levels CHX1, CHX2 and Saline.
- Observation
Categoric factor with levels 1-72.
Source
Newcombe, R.G., Addy, M. and McKeown, S. (1995). "Residual effect of chlorhexidine gluconate in 4-day plaque regrowth crossover trials, and its implications for study design". *Journal of Periodontal Research*, 30, 5, pp. 319-324.
Examples
data("dental")
dental