manova5050 {ffmanova}

Computation of 50-50 MANOVA results

Description

The function takes a design-with-responses object created by xy_Obj and produces 50-50 MANOVA output. Results are produced for each term in the model.

Usage

manova5050(xyObj, stand)

Arguments

xyObj

design-with-responses object

stand

standardisation of responses (0 or 1)

Details

Classical multivariate ANOVA (MANOVA) are useless in many practical cases. The tests perform poorly in cases with several highly correlated responses and the method collapses when the number of responses exceeds the number of observations. 50-50 MANOVA is made to handle this problem. Principal component analysis (PCA) is an important part of this methodology. Each test is based on a separate PCA.

Value

A list with components

termNames

model term names

exVarSS

explained variances calculated from sums of squares summed over all responses

df

degrees of freedom - adjusted for other terms in model

df_om

degrees of freedom - adjusted for terms contained in actual term

nPC

number of principal components used for testing

nBU

number of principal components used as buffer components

exVarPC

variance explained by nPC components

exVarBU

variance explained by (nPC+nBU) components

pValues

50-50 MANOVA p-values

stand

logical. Whether the responses are standardised.

Note

The 50-50 MANOVA p-values are based on the Hotelling-Lawley Trace Statistic. The number of components for testing and the number of buffer components are chosen according to default rules.

Author(s)

Øyvind Langsrud and Bjørn-Helge Mevik

References

Langsrud, Ø. (2002) Rotation Tests. The Statistician, 51, 305–317.

See Also

ffmanova