从一批机器零件毛坯中随机地抽取10件, 测得其重量为(单位:kg): 则这组样本方差是。https://p.ananas.chaoxing.com/star3/origin/3362191579c6445605e19e68c7f34200.png
举一反三
- 在 中, , ,则 等于https://p.ananas.chaoxing.com/star3/origin/98366284d8feecd580613938380206ea.pnghttps://p.ananas.chaoxing.com/star3/origin/526e25c58361a406de96a44862df7aba.pnghttps://p.ananas.chaoxing.com/star3/origin/04970d84ab61ade1077625be94ccdd96.pnghttps://p.ananas.chaoxing.com/star3/origin/7a34359614a39bd8fbffa909e85a630f.png
- 已知某药厂生产的药品袋重服从正态分布,现随机抽取9袋,测得每袋均重15克和标准差3,要求以95%的置信度,估计这批药品每袋重量均值的置信区间(12.694,17.30)(参考值:) https://p.ananas.chaoxing.com/star3/origin/1b5adae303c14ae574e8c3a53a984fa0.pnghttps://p.ananas.chaoxing.com/star3/origin/039b184fcc9539b7acc12c4a00885590.png
- 从一批零件中随机取5只，测得其长度为3.1，2.6，2.8，3.3，2.9，则样本的均值为。
- 设是圆,则https://p.ananas.chaoxing.com/star3/origin/d8b5edc9a2457c461a3685877f8606ab.pnghttps://p.ananas.chaoxing.com/star3/origin/5f3c1256fa1597901980dc868dfb57f7.pnghttps://p.ananas.chaoxing.com/star3/origin/1932e2a8e9452d4d6f94177a0ca40384.pnghttps://p.ananas.chaoxing.com/star3/origin/5785decddcc5b175015fc7c46d4d8405.png
- 以下说法正确的是 https://p.ananas.chaoxing.com/star3/origin/32620d45b840963fcfd2a9e499329436.png https://p.ananas.chaoxing.com/star3/origin/be2489a6491756903a1a67528363e754.png https://p.ananas.chaoxing.com/star3/origin/c5d98544629d58d5c134ed8bc9743922.png https://p.ananas.chaoxing.com/star3/origin/eef7c4f0c58f9f292270fbd5e9600bd3.png