| % File src/library/datasets/man/UCBAdmissions.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{UCBAdmissions} |
| \docType{data} |
| \alias{UCBAdmissions} |
| \title{Student Admissions at UC Berkeley} |
| \description{ |
| Aggregate data on applicants to graduate school at Berkeley for the |
| six largest departments in 1973 classified by admission and sex. |
| } |
| \usage{UCBAdmissions} |
| \format{ |
| A 3-dimensional array resulting from cross-tabulating 4526 |
| observations on 3 variables. The variables and their levels are as |
| follows: |
| |
| \tabular{rll}{ |
| No \tab Name \tab Levels\cr |
| 1 \tab Admit \tab Admitted, Rejected\cr |
| 2 \tab Gender \tab Male, Female\cr |
| 3 \tab Dept \tab A, B, C, D, E, F |
| } |
| } |
| \details{ |
| This data set is frequently used for illustrating Simpson's paradox, |
| see Bickel \emph{et al} (1975). At issue is whether the data show evidence |
| of sex bias in admission practices. There were 2691 male applicants, |
| of whom 1198 (44.5\%) were admitted, compared with 1835 female |
| applicants of whom 557 (30.4\%) were admitted. This gives a sample |
| odds ratio of 1.83, indicating that males were almost twice as likely |
| to be admitted. In fact, graphical methods (as in the example below) |
| or log-linear modelling show that the apparent association between |
| admission and sex stems from differences in the tendency of males and |
| females to apply to the individual departments (females used to apply |
| \emph{more} to departments with higher rejection rates). |
| |
| This data set can also be used for illustrating methods for graphical |
| display of categorical data, such as the general-purpose \link{mosaicplot} |
| or the \link{fourfoldplot} for 2-by-2-by-\eqn{k} tables. |
| } |
| \references{ |
| Bickel, P. J., Hammel, E. A., and O'Connell, J. W. (1975). |
| Sex bias in graduate admissions: Data from Berkeley. |
| \emph{Science}, \bold{187}, 398--403. |
| \url{http://www.jstor.org/stable/1739581}. |
| } |
| \examples{ |
| require(graphics) |
| ## Data aggregated over departments |
| apply(UCBAdmissions, c(1, 2), sum) |
| mosaicplot(apply(UCBAdmissions, c(1, 2), sum), |
| main = "Student admissions at UC Berkeley") |
| ## Data for individual departments |
| opar <- par(mfrow = c(2, 3), oma = c(0, 0, 2, 0)) |
| for(i in 1:6) |
| mosaicplot(UCBAdmissions[,,i], |
| xlab = "Admit", ylab = "Sex", |
| main = paste("Department", LETTERS[i])) |
| mtext(expression(bold("Student admissions at UC Berkeley")), |
| outer = TRUE, cex = 1.5) |
| par(opar) |
| } |
| \keyword{datasets} |