In statistical software like MINITAB and SAS, the default alpha value (critical p-value) is set as 0.15. I would like to know (1) if there is any statistic basis to set it as 0.15 and (2) if this is a common accepted value in statistics. 

I have found that in [this question][1], the critical p-value of 0.15 in R is actually based on AIC. So is AIC the basis to set 0.15 as default value?

Thanks in advance for your help!


  [1]: http://stats.stackexchange.com/questions/97257/stepwise-regression-in-r-critical-p-value