grt (version 0.1-2)

mcovs: Calculate sample means and covariance(s) of multivariate data

Description

Calculate sample means and covariance(s) of multivariate data

Usage

## S3 method for class 'default':
mcovs(x, grouping, pooled=TRUE, \dots)
## S3 method for class 'formula':
mcovs(formula, data, pooled=TRUE, \dots)

Arguments

formula

A formula in the form of grouping ~ x1 + x2 + ..., where the right hand side specifies the sample variables.

data

Data frame from which variables specified in formula are taken.

x

data frame or Matrix containing sample values.

grouping

a factor specifying the population to which the samples in x belong.

pooled

logical. If TRUE, pooled variance-covariance matrix is calculated. If FALSE, a list of variance-covariance matrices for each groups are calculated. Default to TRUE.

...

further arguments

Value

• A list containing:
• N
  total number of samples.
• counts
  number of samples per groups.
• lev
  levels of the grouping factor
• means
  a named list of vectors specifying the means for each group. Named according to lev.
• covs
  a named list of variance-covarinace matrix(es). Named as pooled if pooled=TRUE, otherwise according to lev.