MathGrades: Grades on 5 mathematics tests from Mardia, Kent and Bibby

In ralmond/CPTtools: Tools for Creating Conditional Probability Tables

Grades on 5 mathematics tests from Mardia, Kent and Bibby

Description

Summary statistics for a data set consisting of marks on five mathematics exams originally presented in Mardia, Kent and Bibby (1979). The raw data are not given, but rather the summary statistics reported in Whittaker (1990) are provided.

Usage

data(MathGrades)

Format

A list consisting of the following components:

varnames

Names of the five tests.

means

Average score on each test.

var

Covariance matrix.

cor

Correlation matrix.

icdiag

Diagonal of the inverse covariance matrix.

pcor

Partial correlation (scaled inverse correlation) matrix.

pvecs

A set of marginal distributions for discrete variables corresponding to the five assessments.

Source

Summary statistics reported here are taken from Whittaker (1990).

Original data on 88 students is reported in Mardia, Kent and Bibby (1979).

References

Mardia, K.V. and Kent, J.T. and Bibby, J.M. (1979) Multivariate Analysis. Academic Press.

Whittaker, J. (1990). Graphical Models in Applied Multivariate Statistics. Wiley.

Examples

data(MathGrades)

##Note:  Some of these tests may return false due to machine precision
##issues. 
round(scaleMatrix(MathGrades$var),2) == MathGrades$cor
round(diag(solve(MathGrades$cor)),2) == MathGrades$icdiag
round(scaleMatrix(solve(MathGrades$cor)),2) == MathGrades$pcor

ralmond/CPTtools documentation built on Dec. 27, 2024, 7:15 a.m.