• 2022-07-27
    设X~N(3,4),则下列式子一定成立的是
    A: [img=171x25]1803da1597b071a.png[/img]
    B: [img=171x25]1803da15a10a676.png[/img]
    C: [img=203x29]1803da15a8f3c7e.png[/img]
    D: [img=171x25]1803da15b291aad.png[/img]