Thank you Aftab57. Always helpful. Have you been through it, too? However, this is a new edition, so more recent meta-analytic studies being considered.
That chapter on teachers is fantastic. Makes us re-re-rethink, doesn�t it? 
 
And what about those 5 lines on homogeneous groups? I never liked this idea of homogeneous groups, seems I had some  reasons on my behalf; sometimes I just caught things intuitively.
 
Hello, Eng! Yes, I guess you�re right about the size. But it�s a good book. Besides, we can always use some to correct our posture, can�t we?
Best regards  to all.