print.polycor {polycor}

Standard Methods for polycor Objects

Description

Some standard methods for objects of class polycor, produced by polychor and polyserial, including print, summary, coef, and vcov. The summary method simply invokes the print method.

Usage

## S3 method for class 'polycor'
print(x, digits = max(3, getOption("digits") - 3), ...)
## S3 method for class 'polycor'
summary(object, ...)
## S3 method for class 'polycor'
coef(object, correlation=TRUE, thresholds=TRUE, ...)
## S3 method for class 'polycor'
vcov(object, correlation=TRUE, thresholds=TRUE, ...)

Arguments

x, object

an object of class polycor, as returned by polychor or polyserial.

digits

number of significant digits to be printed.

correlation

return the estimated correlation or sampling variance of the correlation.

thresholds

return the estimated thresholds or sampling variances/covariances of the thresholds.

...

pass arguments from summary to print; otherwise not used.

Author(s)

John Fox [e-mail]

See Also

polychor, polyserial

Examples

if(require(mvtnorm)){
    set.seed(12345)
    data <- rmvnorm(1000, c(0, 0), matrix(c(1, .5, .5, 1), 2, 2))
    x <- data[,1]
    y <- data[,2]
    cor(x, y) # sample correlation
    }
if(require(mvtnorm)){
    x <- cut(x, c(-Inf, .75, Inf))
    y <- cut(y, c(-Inf, -1, .5, 1.5, Inf))
    print(polychor(x, y, ML=TRUE, std.err=TRUE), 
      digits=3)  # polychoric correlation, ML estimate
    }
if(require(mvtnorm)){
    coef(polychor(x, y, ML=TRUE, std.err=TRUE))
    }
if(require(mvtnorm)){
    vcov(polychor(x, y, ML=TRUE, std.err=TRUE))
    }