plotHotellingEllipse {mdatools} | R Documentation |
Add Hotelling ellipse to a scatter plot
plotHotellingEllipse(p, conf.lim = 0.95, col = "#a0a0a0", lty = 3, ...)
p |
plot series (e.g. from PCA scores plot) |
conf.lim |
confidence limit |
col |
color of the ellipse line |
lty |
line type (e.g. 1 for solid, 2 for dashed, etc.) |
... |
any argument suitable for |
The method is created to be used with PCA and PLS scores plots, so it shows the statistical
limits computed using Hotelling T^2 distribution in form of ellipse. The function works similar
to plotConvexHull
and plotConfidenceEllipse
but does not require
grouping of data points. Can be used together with functions plotScores.pca
,
plotScores.ldecomp
, plotXScores.pls
,
plotXScores.plsres
.
See examples for more details.
# create PCA model for People data data(people) m <- pca(people, 4, scale = TRUE) # make scores plot and show Hotelling ellipse with default settings p <- plotScores(m, xlim = c(-8, 8), ylim = c(-8, 8)) plotHotellingEllipse(p) # make scores plot and show Hotelling ellipse with manual settings p <- plotScores(m, xlim = c(-8, 8), ylim = c(-8, 8)) plotHotellingEllipse(p, conf.lim = 0.99, col = "red") # in case if you have both calibration and test set, 'plotScores()' returns # plot series data for both, so you have to subset it and take the first series # (calibration set) as shown below. ind <- seq(1, 32, by = 4) xc <- people[-ind, , drop = FALSE] xt <- people[ind, , drop = FALSE] m <- pca(xc, 4, scale = TRUE, x.test = xt) p <- plotScores(m, xlim = c(-8, 8), ylim = c(-8, 8)) plotHotellingEllipse(p[[1]])