问一道统计学问题：英文Supposeapopulationhasameanof90andastandarddeviationof28.Ifarandomsampleofsize49isdrawnfromthepopulation,theprobabilityofdrawingasamplewithameanofmorethan95is_________.Selectone:

　　问一道统计学问题：英文

　　Supposeapopulationhasameanof90andastandarddeviationof28.Ifarandomsampleofsize49isdrawnfromthepopulation,theprobabilityof

　　drawingasamplewithameanofmorethan95is_________.

　　Selectone:

　　a.0.3944

　　b.1.0000

　　c.0.8944

　　d.0.4286

　　e.0.1056

　　我总觉得是a,但是不是应该X2的吗?为什么?