Computes a statistic based on the Lagrange Multiplier (LM) test of Engle (1982) for autoregressive conditional heteroscedasticity (ARCH). The statistic returned is the $$R^2$$ value of an autoregressive model of order lags applied to $$x^2$$.

stat_arch_lm(x, lags = 12, demean = TRUE)

## Arguments

x a univariate time series Number of lags to use in the test Should data have mean removed before test applied?

A numeric value.