testcorr (version 0.3.0)

iid.test: Testing iid property

Description

The function iid.test computes the test statistics for examining the null hypothesis of i.i.d. property for univariate series given in Dalla, Giraitis and Phillips (2022).

Usage

iid.test(x, max.lag, m0 = 1, alpha = 0.05,
         plot = TRUE, var.name = NULL, scale.font = 1)

Value

An object of class "iid.test", which is a list with the following components:

lag

The lags of the test statistics.

jab

The \(J_{x,|x|}\) test statistics.

pvjab

The p-values for the \(J_{x,|x|}\) test statistics.

jsq

The \(J_{x,x^2}\) test statistics.

pvjsq

The p-values for the \(J_{x,x^2}\) test statistics.

lagc

The lags of the cumulative test statistics.

cab

The \(C_{x,|x|}\) test statistics.

pvcab

The p-values for the \(C_{x,|x|}\) test statistics.

csq

The \(C_{x,x^2}\) test statistics.

pvcsq

The p-values for the \(C_{x,x^2}\) test statistics.

alpha

Significance level for hypothesis testing used in the plots.

varname

The variable name used in the plots/table.

Arguments

x

A numeric vector or a univariate numeric time series (ts, xts, zoo) object or a data frame variable.

max.lag

Maximum lag at which to calculate the test statistics.

m0

Minimum lag at which to calculate the cumulative test statistics. Default is 1.

alpha

Significance level for hypothesis testing used in the plots. Default is 0.05.

plot

Logical. If TRUE, 1) the test statistics (J) and their critical values are plotted and 2) the cumulative test statistics (C) with their critical values are plotted. Default is TRUE. Can be a logical vector for each of the plots 1)-2).

var.name

NULL or a character string specifying the variable name. If NULL and x has name, the name of x is used. If NULL and x has no name, the string "x" is used. Default is NULL.

scale.font

A positive number indicating the scaling of the font size in the plots. Default is 1.

Author

Violetta Dalla, Liudas Giraitis and Peter C. B. Phillips

Details

The \(J_{x,|x|}\) and \(J_{x,x^2}\) statistics are for testing the null hypothesis of i.i.d. at lag \(k\), \(k=1,...,max.lag\), and the \(C_{x,|x|}\) and \(C_{x,x^2}\) statistics are for testing the null hypothesis of i.i.d. at lags \(m_0,...,m\), \(m=m_0,...,max.lag\).

References

Dalla, V., Giraitis, L. and Phillips, P. C. B. (2022). "Robust Tests for White Noise and Cross-Correlation". Econometric Theory, 38(5), 913-941, tools:::Rd_expr_doi("doi:10.1017/S0266466620000341"). Cowles Foundation, Discussion Paper No. 2194RS, https://elischolar.library.yale.edu/cowles-discussion-paper-series/57/.

Examples

x <- rnorm(100)
iid.test(x, max.lag = 10)