Abstract: We derive the joint asymptotic distribution of the sample autocorrelation functions of lag i, i=1,...,l, based on the residuals {Rt}, t=1,2,...n , obtained after fitting a nonlinear time series model. Tests of fit based on the residuals and on the autocorrelations of residuals are also presented. Some simulation results are reported.
Key words and phrases: Nonlinear time series, diagnostic testing, residual autocorrelations, asymptotic distributions, conditional least squares.