设是来自的样本,则( )是总体均值的无偏估计。68f842291f0e802af2867cda01d77499.gif9fef2825bfebcef2c248e463f14416a5.gifba9b1bd7c5fa72bc3d1490bf47130fe9.gif

时间:2022-11-16 22:49:43

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