tperm.fd {fda}R Documentation

Permutation t-test for two groups of functional data objects.

Description

tperm.fd creates a null distribution for a test of no difference between two groups of functional data objects.

Usage

 tperm.fd(x1fd, x2fd, nperm=200, q=0.05, argvals=NULL, plotres=TRUE,...)

Arguments

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.
argvals If yfdPar is a fd object, the points at which to evaluate the point-wise F-statistic.
q Critical upper-tail quantile of the null distribution to compare to the observed F-statistic.
plotres Argument to plot a visual display of the null distribution displaying the 1-qth quantile and observed F-statistic.
... Additional plotting arguments that can be used with plot.

Details

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.

Value

A list with components

pval the observed p-value of the permutation test.
qval the qth quantile of the null distribution.
Tobs the observed maximal t-statistic.
Tnull a vector of length nperm giving the observed values of the permutation distribution.
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 qth quantiles of the null distribution
argvals argument values for evaluating the F-statistic if yfdParis a functional data object.

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Side Effects

a plot of the functional observations

Source

Ramsay, James O., and Silverman, Bernard W. (2006), Functional Data Analysis, 2nd ed., Springer, New York.

See Also

fRegress Fstat.fd


[Package fda version 2.0.2 Index]