2.设随机变量X~N(0,1),令Y=-2X-2,则Y~( ).A. N(-2,-4)B. N(0,1)C. N(-2,4)D. N(2,4)

用热敏测温仪间接测量地热勘探井底温度,重复测量7次,测得温度(单值:℃)为:112.0, 113.4, 111.2, 112.0,114.5,112.9,113.6。而用某精确办法测得温度为112.6(可看作真值),试问用热敏电阻测温仪间接测温有无系统偏差(a=0.05)。____(有/无),选择的检验类型为­­­____检验,自由度为____,­____侧检验,否定域临界值____.

病例对照研究中,选择对照的方法主要有匹配和非匹配两种方法,那么下列可以作为匹配变量的是()A. 疾病因果链上的中间变量B. 只与可疑病因有关而与疾病无关的因素C. 如果避孕药的使用与宗教信仰有关,那么宗教信仰可以作为匹配因素D. 已知的混杂因素

38.判断题(1分)聚类的准则是最小化簇间距离，最大化簇内距离。()A. 对B. 错

一批零件的长度服从正态分布,从中任取16个测得如下数据2.14,2.10,2.13,2.15,2.13,2.12,2.13,2.10,2.15,2.12,2.14,2.10,2.13,2.11,2.14,2.11。对α=0.05,求总体均值的置信区间。(1)已知总体标准差=0.01 (2)总体标准差未知

得分 九、(8分)假设某汽车零部件供应商生产某种规格的轴承,在正常情况下,-|||-其直径(单位:mm )服从正态分布N (50,0.25).为了检测该供应商某天生产的轴承直径是-|||-否正常,在生产的轴承中随机抽查了25只,测得此样本直径均值为50.32。在显著性水平-|||-alpha =0.05 下,根据这批样本数据判断这天生产的轴承的直径是否正常?( _(0.025)=1.96,-|||-_(0.05)=1.65 _(0.025)(24)=2.064 _(0.05)(24)=1.711 _(0.025)(25)-2.059 ._(0.0)(25)=1.708

四、假设甲乙两种投资策略的每万元日收益分别服从N(1,2),N(0.5,1)，各观察30天的日收益，样本方差分别为2.25,1.12，求P(S_(甲)^2/S_(乙)^2>2).（提示：F_(0.5)(29,29)=1）

11.在总体Xsim N(12,2^2)中随机抽取一个容量为5的样本X_(1),X_(2),...,X_(5)，其顺序统计量为X_((1)),X_((2)),...,X_((5))，试求：(1)PX_{(5))<15}；(2)PX_{(1))<10}.(Phi(1.5)=0.9332;Phi(1)=0.8413)

四、我国26个城市1~12月空气质量综合指数月均值如下表4所示,试月份为横坐标,绘制折线图。 (10分)表4 26个城市1~12月空气质量综合指数表空气质量综合指数123456789101112A13.904.163.233.203.202.842.202.142.536.124.286.39B13.803.923.273.523.703.132.242.792.25.094.025.13C16.004.584.153.404.383.403.303.433.314.494.546.09D1..203.844.223.484.053.243.293.203.484.444.075.12E26.509.226.935.626.706.545.075.086.258.307.251..22F10.405.225.384.634.564.893.863.803.925.475.155.39G15.507.786.925.083.833.383.783.884.585.763.798.00H8.804.296.114.653.383.363.293.543.623.474.284.79I15.207.395.292.933.033.163.263.433.883.965.094.35J9.703.175.243.143.093.334.133.112.263.264.283.79K1..404.063.283.303.082.561.671.882.653.794.895.42L1..905.656.814.423.823.523.423.653.274.713.855.89M6.202.853.693.882.592.721.782.342.993.042.933.28N8.102.453.662.872.662.691.442.212.803.452.563.85O7.502.333.332.832.972.511.862.393.344.763.815.27P6.302.172.472.762.762.402.012.372.012.772.262.72Q16.206.214.524.484.965.014.063.794.555.654.786.44R12.504.304.384.034.053.282.493.094.435.684.776.60

设X1,X2,X3,X4,X5是来自正态总体X1,X2,X3,X4,X5的样本.(1) 求C使统计量X1,X2,X3,X4,X5服从X1,X2,X3,X4,X5分布;(2) 求X1,X2,X3,X4,X5所服从的分布.