Australian twin sample biometric data.

Description

Australian data on body mass index (BMI) assessed in both MZ and DZ twins, and saved in the text file twinData.txt.

It is a wide dataset, with two individuals per line. Data include zygosity (zyg), along with heights in metres, weights in kg, and the derived variables BMI in kg/m^2 (stored as "htwt1" and "htwt2"), as well as the log of this variable, stored here as bm1 and bm2. The logged values are more closely normally distributed.

Age of course occurs only once, as the two twins of each pair share a common age. fam is a family identifier.

Usage

data(twinData)

Format

A data frame with 3808 observations on the following 12 variables.

fam

a numeric vector

age

a numeric vector

zyg

a numeric vector

part

a numeric vector

wt1

a numeric vector

wt2

a numeric vector

ht1

a numeric vector

ht2

a numeric vector

htwt1

a numeric vector

htwt2

a numeric vector

bmi1

a numeric vector

bmi2

a numeric vector

Details

Zygosity is coded as follows 1 == MZ females 2 == MZ males 3 == DZ females 4 == DZ males 5 == DZ opposite sex pairs

Examples

data(twinData)
str(twinData)
plot(wt1~wt2, data=twinData)
mzData <- as.matrix(subset(myTwinData, zyg==1, c(bmi1,bmi2)))
dzData <- as.matrix(subset(myTwinData, zyg==3, c(bmi1,bmi2)))