vcdExtra (version 0.7-1)

PhdPubs: Publications of PhD Candidates

Description

A data set giving the number of publications by doctoral candidates in biochemistry in relation to various predictors, originally from Long (1997).

There is a large number of zero counts. Is there evidence for a separate group of non-publishers?

Usage

data(PhdPubs)

Format

A data frame with 915 observations on the following 6 variables.

articles

number of articles published in the final three years of PhD studies

female

dummy variable for gender, coded 1 for female

married

dummy variable for marital status, coded 1 for married

kid5

number of young children, age 5 and under

phdprestige

prestige of the PhD department

mentor

number of publications by the mentor in the preceeding three years

Examples

# NOT RUN {
data(PhdPubs)
# very uninformative
hist(PhdPubs$articles, breaks=0:19, col="pink", xlim=c(0,20),
     xlab="Number of Articles")

library(vcd)
rootogram(goodfit(PhdPubs$articles), xlab="Number of Articles")
# compare with negative binomial
rootogram(goodfit(PhdPubs$articles, type="nbinomial"), 
	xlab="Number of Articles", main="Negative binomial")


# }