对球的直径作近似测量，设其值均匀分布在区间 内，则球体体积的期望为 (球体体积公式为，R为半径)https://img-ph-mirror.nosdn.127.net/qIS-8B7etS4gXbFMUDWsAA==/6608869725445545068.pnghttps://dss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1589698444,631415840&
对球的直径作近似测量，设其值均匀分布在区间 内，则球体体积的期望为 (球体体积公式为，R为半径)https://img-ph-mirror.nosdn.127.net/qIS-8B7etS4gXbFMUDWsAA==/6608869725445545068.pnghttps://dss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=1589698444,631415840&
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