单选
在假设检验中,H0为待检假设,犯第一类错误的是()
A H0成立,经检验接受H0 B H0成立,经检验拒绝H0 C H0不成立,经检验接受H0 D H0不成立,经检验拒绝H0
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单选
x1,x2,…,xn是从正态总体N(μ,σ2)中抽取的样本,若σ2已知,,则μ的置信水平为0.95的置信区间是()
A <img src="https://www.beizhujiaoyu.com/uploads/202208/161223783873921.png" width="240" height="40" />  B <img src="https://www.beizhujiaoyu.com/uploads/202208/161223785142911.png" width="230" height="40" />  C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223785663621.png" width="233" height="40" />  D <img src="https://www.beizhujiaoyu.com/uploads/202208/16122378601811.png" width="233" height="39" /> 
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单选
总体X~N(μ,1),x1,x2,x3。为样本,按照有效性的标准,下面四个关于μ的无偏估计中最好的一个是()
A <img src="https://www.beizhujiaoyu.com/uploads/202208/161223897087971.png" width="88" height="32" />  B <img src="https://www.beizhujiaoyu.com/uploads/202208/161223897495441.png" width="144" height="31" />  C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223897997831.png" width="88" height="32" />  D <img src="https://www.beizhujiaoyu.com/uploads/202208/161223898472621.png" width="144" height="32" /> 
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单选
A 0.95 B 0.05 C 0.975 D 0.025
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单选
设x1,x2,…,xn为来自总体X的样本(n>1),且D(X)=σ2,则σ2的无偏估计量为()
A <img src="https://www.beizhujiaoyu.com/uploads/202208/16122398863891.png" width="135" height="39" />  B <img src="https://www.beizhujiaoyu.com/uploads/202208/16122398916531.png" width="112" height="39" />  C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223989692651.png" width="135" height="39" />  D <img src="https://www.beizhujiaoyu.com/uploads/202208/16122399004141.png" width="135" height="39" /> 
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单选
A <img src="https://www.beizhujiaoyu.com/uploads/202208/161223992065651.png" width="32" height="52" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/161223992617121.png" width="32" height="52" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223993083971.png" width="17" height="37" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/161223993560641.png" width="20" height="62" />
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单选
总体X服从[0,θ]上的均匀分布,θ>0,抽取样本x1,x2,…,xn,若用矩估计法求出θ的估计量为,则()
A <img src="https://www.beizhujiaoyu.com/uploads/202208/161224081394251.png" width="91" height="39" />  B <img src="https://www.beizhujiaoyu.com/uploads/202208/161224081833941.png" width="91" height="39" />  C <img src="https://www.beizhujiaoyu.com/uploads/202208/161224082373301.png" width="79" height="39" />  D <img src="https://www.beizhujiaoyu.com/uploads/202208/161224082890851.png" width="90" height="39" /> 
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分析
填空题:
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分析
填空题:已知某批材料的抗断强度X~N(μ,0.09),现从中抽取容量为9的样本,得样本均值x=8.54,已知u0.025=1.96,则置信度为0.95时μ的置信
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分析
填空题:设总体X~N(μ,σ2),其中σ2未知,现由来自总体X的一个样本x1,x2,…,x9算得样本均值=15,样本标准差s=3,已知t0.025(8)=2.3
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