Lm.test: The Lagrange Multiplier test for arch effect.

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/Lm_test.R

Description

Performs the Lagrange Multipliers test for homoscedasticity in a stationary process. The null hypothesis (H0), is that the process is homoscedastic.

Usage

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Lm.test(y,lag.max = 2,alpha = 0.05)

Arguments

y

a numeric vector or an object of the ts class containing a stationary time series.

lag.max

an integer with the number of used lags.

alpha

Level of the test, possible values range from 0.01 to 0.1. By default alpha = 0.05 is used.

Details

The Lagrange Multiplier test proposed by Engle (1982) fits a linear regression model for the squared residuals and examines whether the fitted model is significant. So the null hypothesis is that the squared residuals are a sequence of white noise, namely, the residuals are homoscedastic.

Value

a h.test class with the main results of the Lagrage multiplier hypothesis test. The h.test class have the following values:

Author(s)

A. Trapletti and Asael Alonzo Matamoros

References

Engle, R. F. (1982). Auto-regressive Conditional Heteroscedasticity with Estimates of the Variance of United Kingdom Inflation. Econometrica. 50(4), 987-1007.

McLeod, A. I. and W. K. Li. (1984). Diagnostic Checking ARMA Time Series Models Using Squared-Residual Auto-correlations. Journal of Time Series Analysis. 4, 269-273.

See Also

arch.test

Examples

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# generating an stationary arma process
y = arima.sim(100,model = list(ar = 0.3))
Lm.test(y)

nortsTest documentation built on June 17, 2021, 5:06 p.m.