mice (version 3.17.0)

potthoffroy: Potthoff-Roy data

Description

Data from Potthoff-Roy (1964) with repeated measures on dental fissures.

Format

tbs is a data frame with 27 rows and 6 columns:

id

Person number

sex

Sex M/F

d8

Distance at age 8 years

d10

Distance at age 10 years

d12

Distance at age 12 years

d14

Distance at age 14 years

Details

This data set is the famous Potthoff-Roy data, used to demonstrate MANOVA on repeated measure data. Potthoff and Roy (1964) published classic data on a study in 16 boys and 11 girls, who at ages 8, 10, 12, and 14 had the distance (mm) from the center of the pituitary gland to the pteryomaxillary fissure measured. Changes in pituitary-pteryomaxillary distances during growth is important in orthodontic therapy. The goals of the study were to describe the distance in boys and girls as simple functions of age, and then to compare the functions for boys and girls. The data have been reanalyzed by many authors including Jennrich and Schluchter (1986), Little and Rubin (1987), Pinheiro and Bates (2000), Verbeke and Molenberghs (2000) and Molenberghs and Kenward (2007). See Chapter 9 of Van Buuren (2012) for a challenging exercise using these data.

Examples

### create missing values at age 10 as in Little and Rubin (1987)

phr <- potthoffroy
idmis <- c(3, 6, 9, 10, 13, 16, 23, 24, 27)
phr[idmis, 4] <- NA
phr

md.pattern(phr)