【单选题】【消耗次数：1】
齐次线性方程组<imgwidth="190"height="84"v:shapes="_x0000_i1169"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image200.png">的自由未知量为（）
①
<imgwidth="40"height="26"v:shapes="_x0000_i1170"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image202.png">
②
<imgwidth="42"height="26"v:shapes="_x0000_i1171"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image204.png">
③
<imgwidth="42"height="26"v:shapes="_x0000_i1172"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image206.png">
④
<imgwidth="40"height="26"v:shapes="_x0000_i1173"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image208.png">
参考答案：
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相关题目
【单选题】
已知<imgwidth="34"height="22"v:shapes="_x0000_i1231"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image291.png">均为<imgwidth="14"height="16"v:shapes="_x0000_i1232"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image293.png">阶方阵且<imgwidth="18"height="18"v:shapes="_x0000_i1233"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image285.png">与<imgwidth="18"height="18"v:shapes="_x0000_i1234"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image295.png">相似，若<imgwidth="56"height="22"v:shapes="_x0000_i1235"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image297.png">，则<imgwidth="24"height="22"v:shapes="_x0000_i1236"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image299.png">为（）
①
<imgwidth="24"height="22"v:shapes="_x0000_i1237"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image301.png">
②
<imgwidth="18"height="18"v:shapes="_x0000_i1238"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image285.png">
③
<imgwidth="18"height="18"v:shapes="_x0000_i1239"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image303.png">
④
<imgwidth="54"height="22"v:shapes="_x0000_i1240"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image305.png">
【单选题】
设<imgwidth="48"height="26"v:shapes="_x0000_i1189"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image226.png">是<imgwidth="16"height="18"v:shapes="_x0000_i1190"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image220.png">的特征值且<imgwidth="54"height="22"v:shapes="_x0000_i1191"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image228.png">，则<imgwidth="26"height="28"v:shapes="_x0000_i1192"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image230.png">是（）特征值
①
<imgwidth="28"height="18"v:shapes="_x0000_i1193"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image232.png">
②
<imgwidth="26"height="22"v:shapes="_x0000_i1194"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image234.png">
③
<imgwidth="22"height="22"v:shapes="_x0000_i1195"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image236.png">
④
<imgwidth="28"height="22"v:shapes="_x0000_i1196"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image238.png">
【单选题】
设<imgwidth="162"height="26"v:shapes="_x0000_i1348"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image448.png">是三阶方阵的三个特征值，对应特征向量分别为<imgwidth="62"height="26"v:shapes="_x0000_i1349"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image450.png">，且存在可逆矩阵<imgwidth="17"height="18"v:shapes="_x0000_i1350"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image452.png">，使得<imgwidth="54"height="22"v:shapes="_x0000_i1351"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image390.png"><imgwidth="118"height="84"v:shapes="_x0000_i1352"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image455.png">，则<imgwidth="32"height="18"v:shapes="_x0000_i1353"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image457.png">（）
①
<imgwidth="78"height="28"v:shapes="_x0000_i1354"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image459.png">
②
<imgwidth="78"height="28"v:shapes="_x0000_i1355"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image461.png">
③
<imgwidth="78"height="28"v:shapes="_x0000_i1356"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image463.png">
④
<imgwidth="78"height="28"v:shapes="_x0000_i1357"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image465.png">
【单选题】
若存在一可逆阵<imgwidth="18"height="18"v:shapes="_x0000_i1303"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image388.png">使得<imgwidth="54"height="22"v:shapes="_x0000_i1304"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image390.png">为对角阵，其中<imgwidth="134"height="84"v:shapes="_x0000_i1305"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image392.png">，则<imgwidth="18"height="18"v:shapes="_x0000_i1306"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image388.png">为（）
①
<imgwidth="84"height="84"v:shapes="_x0000_i1307"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image394.png">
②
<imgwidth="84"height="84"v:shapes="_x0000_i1308"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image394.png">
③
<imgwidth="84"height="84"v:shapes="_x0000_i1309"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image396.png">
④
<imgwidth="84"height="84"v:shapes="_x0000_i1310"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image398.png">
【单选题】
<imgwidth="14"height="16"v:shapes="_x0000_i1205"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image137.png">阶方阵<imgwidth="18"height="18"v:shapes="_x0000_i1206"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image251.png">与<imgwidth="18"height="18"v:shapes="_x0000_i1207"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image253.png">相似的充分必要条件是（）
①
<imgwidth="86"height="22"v:shapes="_x0000_i1208"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image255.png">
②
存在可逆矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1209"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image257.png">与<imgwidth="18"height="24"v:shapes="_x0000_i1210"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image259.png">使得<imgwidth="74"height="24"v:shapes="_x0000_i1211"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image261.png">
③
存在可逆矩阵<imgwidth="16"height="18"v:shapes="_x0000_i1212"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image263.png">使得<imgwidth="82"height="22"v:shapes="_x0000_i1213"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image265.png">
④
存在可逆矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1214"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image257.png">使得<imgwidth="84"height="22"v:shapes="_x0000_i1215"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image268.png">
【单选题】
<imgwidth="44"height="16"v:shapes="_x0000_i1068"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image062.png">矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1069"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的秩为<imgwidth="18"height="16"v:shapes="_x0000_i1070"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">，则（）
①
<imgwidth="18"height="18"v:shapes="_x0000_i1071"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意一个<imgwidth="18"height="16"v:shapes="_x0000_i1072"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">阶子式都不等于零
②
<imgwidth="18"height="18"v:shapes="_x0000_i1073"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意一个<imgwidth="42"height="20"v:shapes="_x0000_i1074"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image068.png">阶子式都不等于零
③
<imgwidth="18"height="18"v:shapes="_x0000_i1075"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意<imgwidth="18"height="16"v:shapes="_x0000_i1076"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">个列向量必线性无关
④
对于任一<imgwidth="18"height="16"v:shapes="_x0000_i1077"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">维列向量<imgwidth="14"height="20"v:shapes="_x0000_i1078"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image070.png">，矩阵<imgwidth="56"height="28"v:shapes="_x0000_i1079"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image072.png">的秩都为<imgwidth="18"height="16"v:shapes="_x0000_i1080"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">
【单选题】
设矩阵<imgwidth="150"height="114"v:shapes="_x0000_i1054"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image038.png">，假设4维列向量组<imgwidth="94"height="26"v:shapes="_x0000_i1055"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image040.png">线性无关，则向量组<imgwidth="142"height="26"v:shapes="_x0000_i1056"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image042.png">的秩为（）
①
<imgwidth="10"height="18"v:shapes="_x0000_i1057"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image044.png">
②
<imgwidth="14"height="18"v:shapes="_x0000_i1058"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image046.png">
③
<imgwidth="14"height="20"v:shapes="_x0000_i1059"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image048.png">
④
<imgwidth="14"height="18"v:shapes="_x0000_i1060"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image050.png">
【单选题】
设<imgwidth="14"height="16"v:shapes="_x0000_i1089"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image004.png">元齐次线性方程组<imgwidth="54"height="20"v:shapes="_x0000_i1090"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image030.png">的通解为<imgwidth="108"height="32"v:shapes="_x0000_i1091"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image083.png">则矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1092"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的秩（）
①
<imgwidth="62"height="24"v:shapes="_x0000_i1093"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image086.png">
②
<imgwidth="90"height="24"v:shapes="_x0000_i1094"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image088.png">
③
<imgwidth="66"height="24"v:shapes="_x0000_i1095"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image079.png">
④
<imgwidth="18"height="18"v:shapes="_x0000_i1096"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的每行元素之和都不等于零
【单选题】
若方阵<imgwidth="100"height="58"v:shapes="_x0000_i1264"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image337.png">，则<imgwidth="18"height="18"v:shapes="_x0000_i1265"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image285.png">的特征方程为（
①
<imgwidth="100"height="58"v:shapes="_x0000_i1266"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image339.png">
②
<imgwidth="112"height="24"v:shapes="_x0000_i1267"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image341.png">
③
<imgwidth="100"height="58"v:shapes="_x0000_i1268"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image343.png">
④
<imgwidth="112"height="24"v:shapes="_x0000_i1269"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image345.png">
【单选题】
若<imgwidth="56"height="22"v:shapes="_x0000_i1197"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image240.png">，则<imgwidth="16"height="18"v:shapes="_x0000_i1198"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image220.png">的特征值为（）
①
<imgwidth="22"height="18"v:shapes="_x0000_i1199"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image242.png">或<imgwidth="10"height="18"v:shapes="_x0000_i1200"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image244.png">
②
<imgwidth="14"height="20"v:shapes="_x0000_i1201"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image246.png">或<imgwidth="10"height="18"v:shapes="_x0000_i1202"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image244.png">
③
<imgwidth="14"height="20"v:shapes="_x0000_i1203"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image246.png">
④
<imgwidth="10"height="18"v:shapes="_x0000_i1204"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image244.png">
【单选题】
设<imgwidth="18"height="18"v:shapes="_x0000_i1034"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">为<imgwidth="14"height="16"v:shapes="_x0000_i1035"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image004.png">阶方阵，<imgwidth="18"height="18"v:shapes="_x0000_i1036"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image010.png">是<imgwidth="18"height="18"v:shapes="_x0000_i1037"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">经过若干次矩阵的初等变换后得到的矩阵，则有（）
①
<imgwidth="64"height="22"v:shapes="_x0000_i1038"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image012.png">
②
<imgwidth="66"height="22"v:shapes="_x0000_i1039"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image014.png">
③
若<imgwidth="54"height="22"v:shapes="_x0000_i1040"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image016.png">，则一定有<imgwidth="54"height="22"v:shapes="_x0000_i1041"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image018.png">
④
<imgwidth="54"height="22"v:shapes="_x0000_i1042"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image020.png">，则一定有<imgwidth="54"height="22"v:shapes="_x0000_i1043"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image022.png">
随机题目
【单选题】
设<img class=jc-formula data-tex={ x }_{ 1 },{ x }_{ 2 },\cdots ,{ x }_{ n } src=https://huaweicloudobs.ahjxjy.cn/DE2C6E0567333C65CDC6AB7F555E2FC7.png style=vertical-align: middle;/>为正态总体<img class=jc-formula data-tex=你N(\mu ,4) src=https://huaweicloudobs.ahjxjy.cn/CC85E3FC72A06153B8AB828C216D5A85.png style=vertical-align: middle;/>的一个样本，<img class=jc-formula data-tex=\overline { x } src=https://huaweicloudobs.ahjxjy.cn/BCCD874E19CEDFF42D493CA7A47C4E90.png style=vertical-align: middle;/>表示样本均值，则<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=vertical-align: middle;/>的置信度为<img class=jc-formula data-tex=1-\alpha src=https://huaweicloudobs.ahjxjy.cn/0D7D8051C64554652E5FBC5A5D64CCE9.png style=vertical-align: middle;/>的置信区间为
①
<img class=jc-formula data-tex=(\overline { x } -{ \mu }_{ \sfrac { \alpha }{ 2 } }\frac { 4 }{ \sqrt { n } } ,\overline { x } +{ \mu }_{ \sfrac { \alpha }{ 2 } }\frac { 4 }{ \sqrt { n } } ) src=https://huaweicloudobs.ahjxjy.cn/F33E4873B4251F8943C2862757F00F41.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=(\overline { x } -{ \mu }_{ \sfrac { 1-\alpha }{ 2 } }\frac { 2 }{ \sqrt { n } } ,\overline { x } +{ \mu }_{ \sfrac { \alpha }{ 2 } }\frac { 2 }{ \sqrt { n } } ) src=https://huaweicloudobs.ahjxjy.cn/E473853FCA813ABD18C5360B410C0EAC.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=(\overline { x } -{ \mu }_{ \alpha }\frac { 2 }{ \sqrt { n } } ,\overline { x } +{ \mu }_{ \alpha }\frac { 2 }{ \sqrt { n } } ) src=https://huaweicloudobs.ahjxjy.cn/6DB869CE7F1D702A8DAEA9DF95D1B9B7.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=(\overline { x } -{ \mu }_{ \sfrac { \alpha }{ 2 } }\frac { 2 }{ \sqrt { n } } ,\overline { x } +{ \mu }_{ \sfrac { \alpha }{ 2 } }\frac { 2 }{ \sqrt { n } } ) src=https://huaweicloudobs.ahjxjy.cn/67FCADC0516F3C051F2DECE09E9DE4B2.png style=vertical-align: middle;/>
【判断题】
样本均值<img class=jc-formula data-tex=\overline { X } =\frac { 1 }{ n } \sum _{ i=1 }^{ n }{ X_{ i } } src=https://huaweicloudobs.ahjxjy.cn/4A97A4928F2A921C0B0FEE9BEA031F02.png style=vertical-align: middle;/>是总体均值EX的一致估计.
①
正确
②
错误
【判断题】
样本方差<img class=jc-formula data-tex=S^2=\frac{1}{n-1}\sum_{i=1}^n{(X_i-\overline{X})^2} src=https://huaweicloudobs.ahjxjy.cn/D58CFC0E67B64DA192511DD78133ECF1.png style=vertical-align: middle;/>是总体方差DX的无偏估计.
①
正确
②
错误
【单选题】
设<img class=jc-formula data-tex={ X }_{ 1 }{ ,X }_{ 2 }{ ,\cdots ,X }_{ n }\quad src=https://huaweicloudobs.ahjxjy.cn/DBF1E4597DFB758D00FD3BE5BEC42B5A.png style=vertical-align: middle;/>为<img class=jc-formula data-tex=X src=https://huaweicloudobs.ahjxjy.cn/18E2773B1E2835B209E7E51B85285E80.png style=vertical-align: middle;/>总体的一个随机样本，<img class=jc-formula data-tex=E(X)=\mu ,D(X)={ \sigma }^{ 2 }, src=https://huaweicloudobs.ahjxjy.cn/76363837713BC0EA3C7D5B8DE88D2A23.png style=vertical-align: middle;/><img class=jc-formula data-tex=\hat { \theta } ^{ 2 }=C\sum _{ i=1 }^{ n-1 }{ { ({ X }_{ i+1 }-{ X }_{ i }) }^{ 2 } } src=https://huaweicloudobs.ahjxjy.cn/D1E258883B355BBE6C9AE03C4C850EB3.png style=vertical-align: middle;/>为 <img class=jc-formula data-tex={ \sigma }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/0CF3AA226894411774EF0AB7244924B1.png style=vertical-align: middle;/>的无偏估计，C＝
①
<img class=jc-formula data-tex=\frac { 1 }{ n } src=https://huaweicloudobs.ahjxjy.cn/935DBCDBF7AAD9823197D86C587EC3A5.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=\frac { 1 }{ n-1 } src=https://huaweicloudobs.ahjxjy.cn/7727714B040BDCFF96E1DCFCEFD8EBF0.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=\frac { 1 }{ 2(n-1) } src=https://huaweicloudobs.ahjxjy.cn/DFF9119B78C5726FC7943427E65E0C9A.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=\frac { 1 }{ n-2 } src=https://huaweicloudobs.ahjxjy.cn/247E111752A300C6EC448FE5CA92D90B.png style=vertical-align: middle;/>
【单选题】
设<img class=jc-formula data-tex=\hat { \theta } src=https://huaweicloudobs.ahjxjy.cn/9CAB6F870853DAF6FBCDD58C16DD47B2.png style=vertical-align: middle;/>是未知参数<img class=jc-formula data-tex=\theta src=https://huaweicloudobs.ahjxjy.cn/9B0901CB3A90E03AB9AFCDB8A3E9E9ED.png style=vertical-align: middle;/>的一个估计量，若<img class=jc-formula data-tex=E\hat { \theta } \neq \theta src=https://huaweicloudobs.ahjxjy.cn/6F6633DB35E25A5A269C21DBA0A6817E.png style=vertical-align: middle;/>，则<img class=jc-formula data-tex=\hat { \theta } src=https://huaweicloudobs.ahjxjy.cn/9CAB6F870853DAF6FBCDD58C16DD47B2.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>是<img class=jc-formula data-tex=\theta src=https://huaweicloudobs.ahjxjy.cn/9B0901CB3A90E03AB9AFCDB8A3E9E9ED.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>的
①
极大似然估计
②
矩法估计
③
相合估计
④
有偏估计
【单选题】
设<img class=jc-formula data-tex={ X }_{ 1 },\cdots ,{ X }_{ n } src=https://huaweicloudobs.ahjxjy.cn/8159F7186DE77C735294288BB1F8C1F1.png style=vertical-align: middle;/>是来自总体<img class=jc-formula data-tex=X src=https://huaweicloudobs.ahjxjy.cn/18E2773B1E2835B209E7E51B85285E80.png style=vertical-align: middle;/>的样本，且<img class=jc-formula data-tex=EX=\mu src=https://huaweicloudobs.ahjxjy.cn/39618736AA44811087C44938D156DBC3.png style=vertical-align: middle;/>，则下列是<img class=jc-formula data-tex=\mu src=https://huaweicloudobs.ahjxjy.cn/44B6A27E434C1345C3CEEB7A5249665D.png style=vertical-align: middle;/>的无偏估计的是
①
<img class=jc-formula data-tex=\frac { 1 }{ n } \sum _{ i=1 }^{ n-1 }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/C47B85208815D85D3DD90DFEC473F7FF.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=\frac { 1 }{ n-1 } \sum _{ i=1 }^{ n }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/F592094A4BE03E45216F0FE940311E37.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=\frac { 1 }{ n } \sum _{ i=2 }^{ n }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/72F0F6F417A0E32959CC0BA9BC395311.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=\frac { 1 }{ n-1 } \sum _{ i=1 }^{ n-1 }{ { X }_{ i } } src=https://huaweicloudobs.ahjxjy.cn/1C176141AB6A855E8CFD52AEF5D595C0.png style=vertical-align: middle;/>
【单选题】
设总体<img class=jc-formula data-tex=X src=https://huaweicloudobs.ahjxjy.cn/18E2773B1E2835B209E7E51B85285E80.png style=vertical-align: middle;/>的数学期望为<img class=jc-formula data-tex=\mu , src=https://huaweicloudobs.ahjxjy.cn/07393889DE1E04D799FC2171DD4841CF.png style=vertical-align: middle;/><img class=jc-formula data-tex={ X }_{ 1 },{ X }_{ 2 },\cdots { X }_{ n } src=https://huaweicloudobs.ahjxjy.cn/7872682357A677F5C3693835FBDE154B.png style=vertical-align: middle;/>为来自<img class=jc-formula data-tex=X src=https://huaweicloudobs.ahjxjy.cn/18E2773B1E2835B209E7E51B85285E80.png style=font-family: 宋体; font-size: 14px; line-height: 24px; white-space: normal; vertical-align: middle;/>的样本，则下列结论中正确的是
①
<img class=jc-formula data-tex={ X }_{ 1 } src=https://huaweicloudobs.ahjxjy.cn/DA66F1A424E4031AEED284B5B6FE9A43.png style=vertical-align: middle;/>是<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=vertical-align: middle;/>的无偏估计量
②
<img class=jc-formula data-tex={ X }_{ 1 } src=https://huaweicloudobs.ahjxjy.cn/DA66F1A424E4031AEED284B5B6FE9A43.png style=white-space: normal; vertical-align: middle;/>是<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>的极大似然估计量
③
<img class=jc-formula data-tex={ X }_{ 1 } src=https://huaweicloudobs.ahjxjy.cn/DA66F1A424E4031AEED284B5B6FE9A43.png style=white-space: normal; vertical-align: middle;/>是<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>的相合（一致）估计量
④
<img class=jc-formula data-tex={ X }_{ 1 } src=https://huaweicloudobs.ahjxjy.cn/DA66F1A424E4031AEED284B5B6FE9A43.png style=white-space: normal; vertical-align: middle;/>不是<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>的估计量
【单选题】
对总体<img class=jc-formula data-tex=X\~ N(\mu ,{ \sigma }^{ 2 }) src=https://huaweicloudobs.ahjxjy.cn/1237A2EB5ED2B9C779BF403A7A4E9EC7.png style=vertical-align: middle;/>的均值<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=vertical-align: middle;/>和作区间估计，得到置信度为95%的置信区间，意义是指这个区间
①
平均含总体95%的值
②
平均含样本95%的值
③
有95%的机会含样本的值
④
有95%的机会的机会含<img class=jc-formula data-tex=\mu \quad src=https://huaweicloudobs.ahjxjy.cn/72143C62DAAAA39AB69A5506838561CA.png style=vertical-align: middle;/>的值
【单选题】
设总体<img class=jc-formula data-tex=X\~ N(\mu ,{ \sigma }^{ 2 }),{ X }_{ 1 },\cdots ,{ X }_{ n } src=https://huaweicloudobs.ahjxjy.cn/77E278627EEB6B30EC2C452582C7E8CD.png style=vertical-align: middle;/>为抽取样本，则<img class=jc-formula data-tex=\frac { 1 }{ n } \sum _{ i=1 }^{ n }{ { ({ X }_{ i }-\overline { X } ) }^{ 2 } } src=https://huaweicloudobs.ahjxjy.cn/28E1CC7702DA75C787BB7DD7A0825DA1.png style=vertical-align: middle;/>是
①
<img class=jc-formula data-tex=\mu src=https://huaweicloudobs.ahjxjy.cn/44B6A27E434C1345C3CEEB7A5249665D.png style=vertical-align: middle; width: 21px; height: 27px; width=21 height=27/>的无偏估计
②
<img class=jc-formula data-tex={ \sigma }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/0CF3AA226894411774EF0AB7244924B1.png style=vertical-align: middle;/>的无偏估计
③
<img class=jc-formula data-tex=\mu src=https://huaweicloudobs.ahjxjy.cn/44B6A27E434C1345C3CEEB7A5249665D.png width=21 height=27 style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle; width: 21px; height: 27px;/>的矩估计
④
<img class=jc-formula data-tex={ \sigma }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/0CF3AA226894411774EF0AB7244924B1.png style=vertical-align: middle;/>的矩估计
【单选题】
设总体X服从正态 <img class=jc-formula data-tex=N(\mu ,\sigma ^{ 2 }) src=https://huaweicloudobs.ahjxjy.cn/AD993E1528D720589A720804B5105B62.png style=vertical-align: middle;/>分布，<img class=jc-formula data-tex=X_1,X_2,\cdots,X_n src=https://huaweicloudobs.ahjxjy.cn/9CB95684AF38E06A798542D3F8B3E3D7.png style=vertical-align: middle;/> 是来自X的简单随机样本，为使 <img class=jc-formula data-tex=A\sum _{ i=1 }^{ n }{ |X_{ i }-\overline { X } | } src=https://huaweicloudobs.ahjxjy.cn/B1F78F20088C852A20F0B9A79EB879F9.png style=vertical-align: middle;/>是<img class=jc-formula data-tex=\sigma src=https://huaweicloudobs.ahjxjy.cn/6C679D32B2AFEAC468E1A6A546D598E3.png style=vertical-align: middle;/> 的无偏估计量，则A的值为
①
<img class=jc-formula data-tex=\frac { 1 }{ \sqrt { n } } src=https://huaweicloudobs.ahjxjy.cn/0159BFD938FCE0D37A92E43005EBE940.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=\frac { 1 }{ n } src=https://huaweicloudobs.ahjxjy.cn/78D4CCDDB5590E6632361E730EE81073.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=\frac { 1 }{ \sqrt { n-1 } } src=https://huaweicloudobs.ahjxjy.cn/C34F54AA8117E47F9D22AE951E93AEA7.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=\sqrt { \frac { \pi }{ 2n(n-1) } } src=https://huaweicloudobs.ahjxjy.cn/ECD912FC37CDC88923C3828625C0BD1F.png style=vertical-align: middle;/>