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?