The National Youth Survey collected a sample of 11 to 17 year olds - 117 boys and 120 girls - asking questions about marijuana usage.
data(potuse)
A data frame with 486 observations on the following 7 variables.
sex
1=Male, 2=Female
year.76
1=never used, 2=used no more than once a month, 3=used more than once a month in 1976
year.77
1=never used, 2=used no more than once a month, 3=used more than once a month in 1977
year.78
1=never used, 2=used no more than once a month, 3=used more than once a month in 1978
year.79
1=never used, 2=used no more than once a month, 3=used more than once a month in 1979
year.80
1=never used, 2=used no more than once a month, 3=used more than once a month in 1980
count
Number of cases in this category
Lang J., McDonald, J and Smith P. (1999) "Association-Marginal Modeling of Mutlivariate Categorical Responses: A Maximum Likelihood Approach" JASA 94, 1161-