标准差的计算
盘编号甲乙丙甲2乙2丙212345合计标准差440460500540560250050.99480490500510520250015.814904955005055107.911936002116002500002916003136002304002401002500002601002704001251000240100245025250000255025260100125025025001260400甲的标准差S??X???X?n22n?11260400?25002/5?＝50.995?1福建医科大学流行病与卫生统计160名正常成年女子的血清甘油三酯（mmol/L）组段（1）0.5～0.6～0.7～频数，f（3）39121321718组中值，X（4）0.550.650.750.951.05fX(5)= (3)×(4)1.655.859.002fX2(5)= (3)×(4) 20.91 3.80 6.75 0.8～0.9～S?1.0～?fX???fX?0.85201.1～1.2～?f?11.1521.25?f11.0516.1518.909.39 15.34 19.85 23.0026.45 22.5028.13 221.5218?182.30/160??0.0869?0.2947171.351.3～22.9530.98 160?1131.451.4～18.8527.33 1.5～1.6～981.551.6513.9513.2021.62 21.78 1.7～1.8合计31601.755.25182.309.19 221.52 福建医科大学流行病与卫生统计
