Perform tests to check the conditional heteroscedasticity in a time series. The Ljung-Box statistics of squared series and a rank-based Ljung-Box
test are used.
Usage
archTest(rt, lag = 10)
Arguments
rt
A scalar time series. If rt is a matrix, only the first column is used.
lag
The number of lags of ACF used in the Ljung-Box statistics. The default is 10.
Value
The Q-statistic and its p-value. Also, the rank-based Q statistic and its p-value.
Details
The Ljung-Box statistics based on the squared series are computed first.
The rank series of the squared time series is than used to test the
conditional heteroscedasticity.