getSSQsweep function

ANOVA Sum of Squares via Sweeping

Compute ANOVA Type-1 sum of squares for linear models.

getSSQsweep(Data, tobj, random = NULL)

Arguments

• Data: (data.frame) with the data
• tobj: (terms) object derived from original formula object
• random: (character) vector, optionally containing information about each model term, whether it is random or fixed (only used in mixed models)

Returns

(list) representing the with variables:

• aov.tab: basic ANOVA-table with degrees of freedom (DF), SS and MS

• Lmat: (list) with components 'Z' and 'A'

Details

This function performs estimation of ANOVA Type-1 sum of squares using the SWEEP-operator (see reference), operating on the augmented matrix $X'X$, where $X$ represents the design matrix not differentiating between fixed and random factors. See the numerical example in Fsweep

exemplifying the type of augmentation of $X'X$ on which sweeping is carried out.

This is an utility function not intended to be called directly. For each term in the formula the design-matrix $Z$ is constructed. Matrix $X$ corresponds to binding all these $Z$-matrices together column-wise.

Degrees of freedom for each term are determined by subtracting the number of linearly dependent columns from the total number of column in X asigned to a specific term.

Examples

## Not run:

data(dataEP05A2_1)
res <- VCA:::getSSQsweep(dataEP05A2_1, terms(y~day/run))
str(res)
## End(Not run)

References

Goodnight, J.H., (1979), A Tutorial on the SWEEP Operator, The American Statistician, 33:3, p.149-158

See Also

Fsweep

Author(s)

Andre Schuetzenmeister andre.schuetzenmeister@roche.com , Florian Dufey florian.dufey@roche.com