This article is part of the R for Researchers series. For a list of topics covered by this series, see the Introduction article. If you're new to R we highly recommend reading the articles in order.

This article has the completed SalDoc.Rmd file. The material explaining the construction of this table are contained in the Data presentation article.

The R chunk options can not be split across multiple lines. These chunk options extend beyond the display box. There is a slider bar at the bottom of the display box which will allow you to scroll to the right to see the remainder of the content.

• The completed SalDoc.Rmd files should look similar to the following

---
title: "Analysis of Professor Salaries"
fontsize: 12pt
geometry: margin=1in
documentclass: article

output:
pdf_document:
fig_caption: yes
---

{r, echo=FALSE}
targetType <- "latex"

#
# table numbers
#
tabNumRankByDscpl <- 1

#
# figure numbers
#
FigNumYrsFacRank <- 1
FigNumBoxDscplFacRank <- 2
FigNumGenYrsFacDscpl <- 3
FigNumBoxGenRankFacDscpl <- 4


{r, echo=FALSE, results="hide", message=FALSE, warning=FALSE, fig.show="hide"}
source("SalAnalysis.R")


## Data overview

The Salaries data set is the basis for this analysis.
It is a sample of academic salaries of Professors at
United States universities from the 2008-9 school year.
The salary information was collected to monitor the
difference in salaries between men and women.

{r, echo=FALSE, results="hide", message=FALSE, warning=FALSE, fig.show="hide"}
vars <- colnames(SalariesIn)
dscplNames <- levels(salary$dscpl) rankNames <- levels(salary$rank)


The data set included r length(salary$salary) professors. The variables included in the data set are r paste(vars[-length(vars)],collapse=", "), and r vars[length(vars)]. The sampled professors had ranks of r paste(rankNames[-length(rankNames)],collapse=", "), and r rankNames[length(rankNames)] and were from disciplines r paste(dscplNames[-length(dscplNames)],collapse=", ") and r dscplNames[length(dscplNames)]. The numbers of professors from each of these groups is displayed in table r tabNumRankByDscpl. There are about 20 percent more members of discipline B included in the sample than of discipline A. The table shows there are a greater proportion of Discipline B members with a rank of associate or assistant professor. {r, echo=FALSE } tempTab <- table(salary$rank,salary$dscpl) rankByDscpl <- as.data.frame.matrix(tempTab) rankByDscpl$Totals <- rowSums(tempTab)
rankByDscpl["Totals",] <- colSums(rankByDscpl)
rankByDscpl


{r, echo=FALSE, results="asis"}
xtab <- xtable(rankByDscpl,
caption="Count of Professors by discipline and Rank",
display=c("s","d","d","d"),
align="|r|rr|r|"
)
print(xtab,
type=targetType,
caption.placement="top",
hline.after=c(-1,0,3,4),
comment=FALSE
)


The relationship between years of service and salary can be
seen in figure r FigNumYrsFacRank.
The panels seem to indicate that for associate and assistant
professors most of the members of discipline B have higher
salaries than most of the members of discipline A, at the
same rank.
The box plots, figure r FigNumBoxDscplFacRank, also supports
this observation.

{r, echo=FALSE, fig.cap="Salaries  by discipline and rank", fig.height=2.75, fig.width=5.5 }
plotYrsFacRank


{r, echo=FALSE, fig.cap="Salaries summarized by discipline and rank", fig.height=2.75, fig.width=5.5 }
boxDscplFacRank


The plots of salaries with color indicators for gender, figure
r FigNumGenYrsFacDscpl, indicates there may be a gender
difference in salary in discipline A.
The box plots in figure r FigNumBoxGenRankFacDscpl
indicate that the difference between the genders in
discipline A is greatest at the rank of assistant professor.

The plots of salaries with color indicators for gender, figure
r FigNumGenYrsFacDscpl, indicates there may be a gender
difference in salary in discipline A.
The box plots in figure r FigNumBoxGenRankFacDscpl indicate
that the difference between the genders in discipline A is
greatest at the rank of assistant professor.

{r, echo=FALSE, fig.cap="Salaries by gender and discipline", fig.height=2.75, fig.width=5.5 }
plotYrsFacDscpl


{r, echo=FALSE, fig.cap="Salaries summarized by gender and discipline", fig.height=3, fig.width=5.5 }
boxGenRankFacDscpl