| % File src/library/datasets/man/ability.cov.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{ability.cov} |
| \docType{data} |
| \alias{ability.cov} |
| \title{Ability and Intelligence Tests} |
| \description{ |
| Six tests were given to 112 individuals. The covariance matrix is |
| given in this object. |
| } |
| \details{ |
| The tests are described as |
| \describe{ |
| \item{general:}{a non-verbal measure of general intelligence using |
| Cattell's culture-fair test.} |
| \item{picture:}{a picture-completion test} |
| \item{blocks:}{block design} |
| \item{maze:}{mazes} |
| \item{reading:}{reading comprehension} |
| \item{vocab:}{vocabulary} |
| } |
| |
| Bartholomew gives both covariance and correlation matrices, |
| but these are inconsistent. Neither are in the original paper. |
| } |
| \usage{ability.cov} |
| \source{ |
| Bartholomew, D. J. (1987). |
| \emph{Latent Variable Analysis and Factor Analysis}. |
| Griffin. |
| |
| Bartholomew, D. J. and Knott, M. (1990). |
| \emph{Latent Variable Analysis and Factor Analysis}. |
| Second Edition, Arnold. |
| } |
| \references{ |
| Smith, G. A. and Stanley G. (1983). |
| Clocking \eqn{g}: relating intelligence and measures of timed |
| performance. |
| \emph{Intelligence}, \bold{7}, 353--368. |
| \doi{10.1016/0160-2896(83)90010-7}. |
| } |
| \examples{\donttest{ |
| require(stats) |
| (ability.FA <- factanal(factors = 1, covmat = ability.cov)) |
| update(ability.FA, factors = 2) |
| ## The signs of factors and hence the signs of correlations are |
| ## arbitrary with promax rotation. |
| update(ability.FA, factors = 2, rotation = "promax") |
| }} |
| \keyword{datasets} |