[Gretl-users] Q-statistic

Dear all: I run ARIMA(1,0,1) by conditional maximum likelyhood. the residual is : table1: uhat2 1980:01 1980:02 -5.421687 1980:03 -0.506024 1980:04 1.867470 1980:05 1.698795 I choose the options /Graphs/--/Risidual correlogram/ output of Residual autocorrelation function shows: table2: LAG ACF PACF Q-stat. [p-value] 1 0.1567 0.1567 0.1964 [0.658] 2 -0.3373 -0.3710 1.5619 [0.458] 3 -0.3194 -0.2244 4.0097 [0.260] I caucualte Q-statistic by the formulation of Ljung-Box statistc from table1, but the values I cauculate by myself seem not equal to the values of table2 (0.1964, 1.5619, and 4.0097) Maybe I mistake somewhere. This question puzzles me.