请教高手:
Correlated Random Effects - Hausman Test
Pool: Untitled
Test cross-section random effects
Test Summary Chi-Sq. Statistic Chi-Sq. d.f. Prob.
Cross-section random 0.000000 2 1.0000
* Cross-section test variance is invalid. Hausman statistic set to zero.
面板数据是城市数据,宽而短型。请问问题出在哪?怎么判断固定或随机效应呢?