Description Usage Arguments Value References See Also Examples

The function implements the Interval Testing Procedure for testing the center of symmetry of a functional population evaluated on a uniform grid. Data are represented by means of the B-spline expansion and the significance of each basis coefficient is tested with an interval-wise control of the Family Wise Error Rate. The default parameters of the basis expansion lead to the piece-wise interpolating function.

1 | ```
ITP1bspline(data, mu = 0, order = 2, nknots = dim(data)[2], B = 1000)
``` |

`data` |
Pointwise evaluations of the functional data set on a uniform grid.
It is a matrix of dimensions |

`mu` |
The center of symmetry under the null hypothesis: either a constant
(in this case, a constant function is used) or a |

`order` |
Order of the B-spline basis expansion. The default is |

`nknots` |
Number of knots of the B-spline basis expansion. The default is |

`B` |
The number of iterations of the MC algorithm to evaluate the p-values of the permutation tests. The defualt is |

`ITP1bspline`

returns an object of `class`

"`ITP1`

".
An object of class "`ITP1`

" 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` |
Center of symmetry under the null hypothesis (as entered by the user). |

`coeff` |
Matrix of dimensions |

`pval` |
Unadjusted p-values for each basis coefficient. |

`pval.matrix` |
Matrix of dimensions |

`adjusted.pval` |
Adjusted p-values for each basis coefficient. |

`labels` |
Labels indicating the population membership of each data (in this case always equal to |

`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). |

A. Pini and S. Vantini (2017). The Interval Testing Procedure: Inference for Functional Data Controlling the Family Wise Error Rate on Intervals. Biometrics 73(3): 835–845.

See also `plot.ITP1`

and `ITPimage`

for plotting the results,
`ITP1fourier`

for ITP based on Fourier basis, `IWT1`

for a one-sample test that is not based on
an a-priori selected basis expansion.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 | ```
# Importing the NASA temperatures data set
data(NASAtemp)
# Performing the ITP for one population with the B-spline basis
ITP.result <- ITP1bspline(NASAtemp$paris,mu=4,nknots=50,B=1000)
# Plotting the results of the ITP
plot(ITP.result,xrange=c(0,12),main='Paris temperatures')
# Plotting the p-value heatmap
ITPimage(ITP.result,abscissa.range=c(0,12))
# Selecting the significant components at 5% level
which(ITP.result$adjusted.pval < 0.05)
``` |

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