[wanhaiyou]

Thanks very much for your patient and kindly help,Clyde. Also, sorry for my bad english. I think I understand now.

Best regards,wanhaiyou

[Carlo Lazzaro]

wanhayou:
along the same lines of Clyde's helpfulf insights, focusing on statistical significance only is not, in general, an advisable attitude.
The lack of statistical significance may well depend on a limited sample size; hence, if you were able to collect more data, the non-significant coefficient might turn out significant other things being equal with your regression model.

[wanhaiyou]

Carlo:
Thanks very much for your inputs.I have learned a lot.

Kind regards,
wanhaiyou