Exercise 4.2

  1. Taking support for abortion as the outcome variable, produce fourfold displays showing the association with sex, stratified by status.
options(repos="https://cran.rstudio.com")
install.packages("vcd")
## 
## The downloaded binary packages are in
##  /var/folders/xj/tl6pm98x5qb3b_94_pxtg29h0000gn/T//Rtmp2LPoas/downloaded_packages
library(vcd)
## Loading required package: grid
install.packages('vcdExtra')
## 
## The downloaded binary packages are in
##  /var/folders/xj/tl6pm98x5qb3b_94_pxtg29h0000gn/T//Rtmp2LPoas/downloaded_packages
library(vcdExtra)
## Loading required package: gnm
data("Abortion",package ="vcdExtra")
str(Abortion)
##  table [1:2, 1:2, 1:2] 171 152 138 167 79 148 112 133
##  - attr(*, "dimnames")=List of 3
##   ..$ Sex             : chr [1:2] "Female" "Male"
##   ..$ Status          : chr [1:2] "Lo" "Hi"
##   ..$ Support_Abortion: chr [1:2] "Yes" "No"
fourfold(aperm(Abortion, c(3, 1, 2)))

(b) Do the same for the association of support for abortion with status, stratified by sex.

fourfold(aperm(Abortion, c(3, 2, 1 )))

(c) For each of the problems above, use oddsratio () to calculate the numerical values of the odds ratio, as stratified in the question.

oddsratio(aperm(Abortion, c(3, 1,2 )))
## log odds ratios for Support_Abortion and Sex by Status 
## 
##          Lo          Hi 
##  0.74554746 -0.01888987
oddsratio(aperm(Abortion, c(3, 2, 1 )))
## log odds ratios for Support_Abortion and Status by Sex 
## 
##     Female       Male 
##  0.5634609 -0.2009764
  1. Write a brief summary of how support for abortion depends on sex and status.

In low status, women tend to suport abortion more than men. While in high status, men tend to support abortion more than women.

Exercise 4.7

  1. Assess the strength of agreement between the raters using Cohen’s κ, both unweighted and weighted.
movies = matrix(c(24,8,13,8,13,11,10,9,64),ncol=3,byrow=TRUE)
colnames(movies) = c("Con","Mixed","Pro")
rownames(movies) = c("Con","Mixed","Pro")
movies = as.table(movies)
addmargins(movies)
##       Con Mixed Pro Sum
## Con    24     8  13  45
## Mixed   8    13  11  32
## Pro    10     9  64  83
## Sum    42    30  88 160
Kappa(movies)
##             value     ASE     z  Pr(>|z|)
## Unweighted 0.3888 0.05979 6.503 7.870e-11
## Weighted   0.4269 0.06350 6.723 1.781e-11
  1. Use agreementplot () for a graphical display of agreement here.
agreementplot(movies, main="Unweighted")

agreementplot(movies, main="Weighted")