ITP2fourier {fdatest} | R Documentation |
Two populations Interval Testing Procedure with Fourier basis
Description
The function implements the Interval Testing Procedure for testing the difference between two functional populations evaluated on a uniform grid. Data are represented by means of the Fourier basis and the significance of each basis coefficient is tested with an interval-wise control of the Family Wise Error Rate.
Usage
ITP2fourier(data1, data2, mu = 0,
maxfrequency=floor(dim(data1)[2]/2), B = 10000, paired = FALSE)
Arguments
data1 |
Pointwise evaluations of the first population's functional data set on a uniform grid. |
data2 |
Pointwise evaluations of the second population's functional data set on a uniform grid. |
mu |
The difference between the first functional population and the second functional population under the null hypothesis. Either a constant (in this case, a constant function is used) or a |
maxfrequency |
The maximum frequency to be used in the Fourier basis expansion of data. The default is |
B |
The number of iterations of the MC algorithm to evaluate the p-values of the permutation tests. The defualt is |
paired |
A logical indicating whether the test is paired. The default is |
Value
ITP2fourier
returns an object of class
"ITP2
".
An object of class "ITP2
" is a list containing at least the following components:
basis |
String vector indicating the basis used for the first phase of the algorithm. In this case equal to |
test |
String vector indicating the type of test performed. in this case equal to |
mu |
Difference between the first functional population and the second functional population under the null hypothesis (as entered by the user). |
paired |
Logical indicating whether the test is paired (as entered by the user). |
coeff |
Matrix of dimensions |
pval |
Uncorrected p-values for each frequency. |
pval.matrix |
Matrix of dimensions |
corrected.pval |
Corrected p-values for each frequency. |
labels |
Labels indicating the population membership of each data. |
data.eval |
Evaluation on a fine uniform grid of the functional data obtained through the basis expansion. |
heatmap.matrix |
Heatmap matrix of p-values (used only for plots). |
Author(s)
Alessia Pini, Simone Vantini
References
A. Pini and S. Vantini (2013). The Interval Testing Procedure: Inference for Functional Data Controlling the Family Wise Error Rate on Intervals. MOX-report 13/2013, Politecnico di Milano.
See Also
See also ITP2pafourier
, ITP2bspline
, ITP1fourier
, ITP1bspline
, and ITPimage
.
Examples
# Importing the NASA temperatures data set
data(NASAtemp)
# Performing the ITP
ITP.result <- ITP2fourier(NASAtemp$milan,NASAtemp$paris,maxfrequency=20,B=1000,paired=TRUE)
# Plotting the results of the ITP
plot(ITP.result,main='NASA data',xrange=c(1,365),xlab='Day')
# Plotting the p-value heatmap
ITPimage(ITP.result,abscissa.range=c(1,365))
# Selecting the significant coefficients
which(ITP.result$corrected.pval < 0.05)