I have written the simplest code with TFP shock, where rhoA=0.97 is persistence.
The theoretical variance should be
theoretical variance=1/(1-rhoA^2)=16.9205
But dynare returns:
"
MOMENTS OF SIMULATED VARIABLES
VARIABLE MEAN STD. DEV. VARIANCE SKEWNESS KURTOSIS
A -0.240878 4.598555 21.146709 0.434870 0.629554
"
so, what is "21.146709", and why mean is negative?