SampleStatistics {cmm}R Documentation

SampleStatistics

Description

Gives sample values, standard errors and z-scores of one or more coefficients.

Usage

SampleStatistics(dat, coeff, CoefficientDimensions="Automatic",
    Labels="Automatic", ShowCoefficients=TRUE, ShowParameters=FALSE, ParameterCoding="Effect", ShowCorrelations=FALSE,  Title="")

Arguments

dat observed data as a list of frequencies or as a data frame
coeff list of coefficients, can be obtained using SpecifyCoefficient
CoefficientDimensions numeric vector of dimensions of the table in which the coefficient vector is to be arranged
Labels list of characters or numbers indicating labels for dimensions of table in which the coefficient vector is to be arranged
ShowCoefficients boolean, indicating whether or not the coefficients are to be displayed
ShowParameters boolean, indicating whether or not the parameters (computed from the coefficients) are to be displayed
ParameterCoding Coding to be used for parameters, choice of "Effect", "Dummy" and "Polynomial"
ShowCorrelations boolean, indicating whether or not to show the correlation matrix for the estimated coefficients
Title title of computation to appear at top of screen output

Details

The data can be a data frame or vector of frequencies. MarginalModelFit converts a data frame dat using c(t(ftable(dat))).

For ParameterCoding, the default for "Dummy" is that the first cell in the table is the reference cell. Cell (i, j, k, ...) can be made reference cell using list("Dummy",c(i,j,k,...)). For "Polynomial" the default is to use centralized scores based on equidistant (distance 1) linear scores, for example, if for i = 1, 2, 3, 4,

mu_i = alpha + q_i beta + r_i gamma + s_i delta

where beta is a quadratic, gamma a cubic and delta a quartic effect, then q_i takes the values (-1.5, -.5, .5, 1.5), r_i takes the values (1, -1, -1, 1) (centralized squares of the q_i), and s_i takes the values (-3.375, -.125, .125, 3.375) (cubes of the q_i).

Value

NA. Only output to the screen is provided

Author(s)

W. P. Bergsma w.p.bergsma@lse.ac.uk

References

Bergsma, W. P. (1997). Marginal models for categorical data. Tilburg, The Netherlands: Tilburg University Press. http://stats.lse.ac.uk/bergsma/pdf/bergsma_phdthesis.pdf

Bergsma, W. P., Croon, M. A., & Hagenaars, J. A. P. (2009). Marginal models for dependent, clustered, and longitudunal categorical data. Berlin: Springer.

See Also

ModelStatistics, MarginalModelFit

Examples

 data(BodySatisfaction)

 ## Table 2.6 in Bergsma, Croon and Hagenaars (2009). Loglinear parameters for marginal table IS
 ## We provide two to obtain the parameters

 dat   <- BodySatisfaction[,2:8]        # omit first column corresponding to gender

 # matrix producing 1-way marginals, ie the 7x5 table IS
 at75 <- MarginalMatrix( c(1, 2, 3, 4, 5, 6, 7), list(c(1),c(2),c(3),c(4),c(5),c(6),c(7)), c(5, 5, 5, 5, 5, 5, 5) )

 # First method: the "coefficients" are the log-probabilities, from which all the (loglinear) parameters are calculated
 SampleStatistics(dat, list("log",at75), CoefficientDimensions=c(7,5),Labels=c("I","S"),ShowCoefficients=FALSE,ShowParameters=TRUE)

 # Second method: the "coefficients" are explicitly specified as being the (highest-order) loglinear parameters
 loglinpar75 <- SpecifyCoefficient("LoglinearParameters", c(7,5) )
 SampleStatistics(dat, list(loglinpar75, at75), CoefficientDimensions=c(7,5), Labels=c("I","S"))

[Package cmm version 0.1 Index]