tperm.fd | R Documentation |
tperm.fd creates a null distribution for a test of no difference between two groups of functional data objects.
tperm.fd(x1fd, x2fd, nperm=200, q=0.05, argvals=NULL, plotres=TRUE, ...)
x1fd |
a functional data object giving the first group of functional observations. |
x2fd |
a functional data object giving the second group of functional observations. |
nperm |
number of permutations to use in creating the null distribution. |
q |
Critical upper-tail quantile of the null distribution to compare to the observed t-statistic. |
argvals |
If |
plotres |
Argument to plot a visual display of the null distribution
displaying the |
... |
Additional plotting arguments that can be used with |
The usual t-statistic is calculated pointwise and the test based on
the maximal value. If argvals
is not specified, it defaults
to 101 equally-spaced points on the range of yfdPar
.
A list with the following components:
pval |
the observed p-value of the permutation test. |
qval |
the |
Tobs |
the observed maximal t-statistic. |
Tnull |
a vector of length |
Tvals |
the pointwise values of the observed t-statistic. |
Tnullvals |
the pointwise values of of the permutation observations. |
pvals.pts |
pointwise p-values of the t-statistic. |
qvals.pts |
pointwise |
argvals |
argument values for evaluating the F-statistic if |
a plot of the functional observations
Ramsay, James O., Hooker, Giles, and Graves, Spencer (2009), Functional data analysis with R and Matlab, Springer, New York.
Ramsay, James O., and Silverman, Bernard W. (2005), Functional Data Analysis, 2nd ed., Springer, New York.
Ramsay, James O., and Silverman, Bernard W. (2002), Applied Functional Data Analysis, Springer, New York.
fRegress
Fstat.fd
oldpar <- par(no.readonly=TRUE)
# This tests the difference between boys and girls heights in the
# Berkeley growth data.
# First set up a basis system to hold the smooths
knots <- growth$age
norder <- 6
nbasis <- length(knots) + norder - 2
hgtbasis <- create.bspline.basis(range(knots), nbasis, norder, knots)
# Now smooth with a fourth-derivative penalty and a very small smoothing
# parameter
Lfdobj <- 4
lambda <- 1e-2
growfdPar <- fdPar(fd(matrix(0,nbasis,1), hgtbasis), Lfdobj, lambda)
hgtmfd <- smooth.basis(growth$age, growth$hgtm, growfdPar)$fd
hgtffd <- smooth.basis(growth$age, growth$hgtf, growfdPar)$fd
# Call tperm.fd
tres <- tperm.fd(hgtmfd,hgtffd)
par(oldpar)
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