On Tue, 17 Jan 2012, Henrique Andrade wrote: If the impulses cross the blue lines on the graph that's saying that the ACF values are significant at the 5 percent significance level, while the single asterisks for lags 7 and 8 represent significance at the 10 percent level. As in gretl's model output, 0.01 < p-value < 0.05 is represented by two asterisks, and p-value < 0.01 by three. So what you're seeing is quite consistent. Allin Cottrell