【单选题】【消耗次数：1】
对总体<imgwidth="84"height="22"v:shapes="_x0000_i1318"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image412.png">的均值<imgwidth="12"height="14"v:shapes="_x0000_i1319"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image414.png">做区间估计，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<imgwidth="12"height="14"v:shapes="_x0000_i1320"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image414.png">的值
④
有95%的机会含样本的值
参考答案：
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相关题目
【单选题】
设<imgwidth="95"height="22"v:shapes="_x0000_i1198"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image265.png">与<imgwidth="78"height="22"v:shapes="_x0000_i1199"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image267.png">都是来自于总体<imgwidth="14"height="14"v:shapes="_x0000_i1200"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image154.png">的两独立样本，<imgwidth="14"height="20"v:shapes="_x0000_i1201"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image268.png">，<imgwidth="12"height="20"v:shapes="_x0000_i1202"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image247.png">与<imgwidth="46"height="22"v:shapes="_x0000_i1203"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image270.png">分别是两样本的均值和方差，<imgwidth="144"height="22"v:shapes="_x0000_i1204"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image272.png">，则有（）
①
对于任意的常数<imgwidth="179"height="22"v:shapes="_x0000_i1205"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image274.png">是<imgwidth="12"height="18"v:shapes="_x0000_i1206"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">的无偏估计，且<imgwidth="73"height="42"v:shapes="_x0000_i1207"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image278.png">，<imgwidth="73"height="42"v:shapes="_x0000_i1208"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image280.png">，<imgwidth="32"height="20"v:shapes="_x0000_i1209"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image282.png">达到最小
②
对于任意的常数<imgwidth="179"height="22"v:shapes="_x0000_i1210"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image274.png">是<imgwidth="12"height="18"v:shapes="_x0000_i1211"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">的无偏估计，且<imgwidth="73"height="42"v:shapes="_x0000_i1212"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image278.png">，<imgwidth="73"height="42"v:shapes="_x0000_i1213"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image280.png">，<imgwidth="32"height="20"v:shapes="_x0000_i1214"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image282.png">达到最小
③
对于任意常数<imgwidth="95"height="29"v:shapes="_x0000_i1215"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image284.png">，<imgwidth="202"height="26"v:shapes="_x0000_i1216"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image286.png">都是<imgwidth="12"height="18"v:shapes="_x0000_i1217"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">的无偏估计，并且当<imgwidth="46"height="40"v:shapes="_x0000_i1218"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image288.png">时，<imgwidth="35"height="20"v:shapes="_x0000_i1219"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image290.png">达到最小
④
对于任意常数<imgwidth="84"height="26"v:shapes="_x0000_i1220"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image291.png">，<imgwidth="207"height="26"v:shapes="_x0000_i1221"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image292.png">都是<imgwidth="12"height="18"v:shapes="_x0000_i1222"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">的无偏估计
【单选题】
设总体<imgwidth="84"height="22"v:shapes="_x0000_i1356"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image412.png">，<imgwidth="20"height="20"v:shapes="_x0000_i1357"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image461.png">未知，<imgwidth="75"height="26"v:shapes="_x0000_i1358"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image476.png">是来自<imgwidth="12"height="14"v:shapes="_x0000_i1359"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image426.png">的样本，<imgwidth="12"height="20"v:shapes="_x0000_i1360"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image478.png">为样本均值，<imgwidth="12"height="14"v:shapes="_x0000_i1361"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image480.png">为样本标准差。是检验问题为<imgwidth="164"height="22"v:shapes="_x0000_i1362"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image482.png">则检验的统计量为（）
①
<imgwidth="135"height="35"v:shapes="_x0000_i1363"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image484.png">
②
<imgwidth="135"height="35"v:shapes="_x0000_i1364"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image486.png">
③
<imgwidth="135"height="37"v:shapes="_x0000_i1365"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image488.png">
④
<imgwidth="115"height="37"v:shapes="_x0000_i1366"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image490.png">
【单选题】
设总体<imgwidth="14"height="14"v:shapes="_x0000_i1259"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image333.png">的分布中带有未知参数<imgwidth="12"height="14"v:shapes="_x0000_i1260"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image334.png">，<imgwidth="86"height="22"v:shapes="_x0000_i1261"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image336.png">为样本，<imgwidth="29"height="26"v:shapes="_x0000_i1262"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image338.png"><imgwidth="109"height="26"v:shapes="_x0000_i1263"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image340.png">和<imgwidth="146"height="26"v:shapes="_x0000_i1264"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image342.png">是参数<imgwidth="12"height="20"v:shapes="_x0000_i1265"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image343.png">的两个无偏估计，若对任意的样本容量<imgwidth="12"height="14"v:shapes="_x0000_i1266"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image345.png">，若<imgwidth="12"height="26"v:shapes="_x0000_i1267"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image346.png">为比<imgwidth="12"height="26"v:shapes="_x0000_i1268"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image347.png">有效的估计量，则必有（）
①
<imgwidth="95"height="26"v:shapes="_x0000_i1269"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image348.png">
②
<imgwidth="95"height="26"v:shapes="_x0000_i1270"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image350.png">
③
<imgwidth="86"height="26"v:shapes="_x0000_i1271"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image352.png">
④
<imgwidth="86"height="26"v:shapes="_x0000_i1272"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image354.png">
【单选题】
设总体<imgwidth="14"height="14"v:shapes="_x0000_i1069"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image002.png">服从两点分布：<imgwidth="259"height="20"v:shapes="_x0000_i1070"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image080.png"><imgwidth="75"height="26"v:shapes="_x0000_i1071"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image081.png">为其样本，则样本均值<imgwidth="12"height="18"v:shapes="_x0000_i1072"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image083.png">的期望<imgwidth="49"height="20"v:shapes="_x0000_i1073"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image085.png">（）
①
<imgwidth="12"height="18"v:shapes="_x0000_i1074"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image087.png">
②
<imgwidth="18"height="22"v:shapes="_x0000_i1075"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image089.png">
③
<imgwidth="32"height="22"v:shapes="_x0000_i1076"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image091.png">
④
<imgwidth="20"height="22"v:shapes="_x0000_i1077"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image093.png">
【单选题】
设总体<imgwidth="14"height="14"v:shapes="_x0000_i1273"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image333.png">服从泊松分布：<imgwidth="217"height="40"v:shapes="_x0000_i1274"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image356.png">，其中<imgwidth="32"height="18"v:shapes="_x0000_i1275"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image358.png">为未知参数，<imgwidth="86"height="22"v:shapes="_x0000_i1276"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image336.png">为样本，记<imgwidth="84"height="40"v:shapes="_x0000_i1277"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image360.png">，则下面几种说法错误的是（）
①
<imgwidth="14"height="18"v:shapes="_x0000_i1278"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image362.png">是<imgwidth="12"height="18"v:shapes="_x0000_i1279"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image364.png">的无偏估计
②
<imgwidth="14"height="18"v:shapes="_x0000_i1280"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image362.png">是<imgwidth="12"height="18"v:shapes="_x0000_i1281"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image364.png">的矩估计
③
<imgwidth="14"height="14"v:shapes="_x0000_i1282"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image365.png">是<imgwidth="35"height="20"v:shapes="_x0000_i1283"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image367.png">的矩估计
④
<imgwidth="14"height="20"v:shapes="_x0000_i1284"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image368.png">是<imgwidth="12"height="37"v:shapes="_x0000_i1285"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image370.png">的矩估计
【单选题】
设<imgwidth="69"height="22"v:shapes="_x0000_i1152"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image208.png">是来自正态总体<imgwidth="58"height="22"v:shapes="_x0000_i1153"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image210.png">的样本,已知统计量<imgwidth="118"height="22"v:shapes="_x0000_i1154"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image212.png">是方差<imgwidth="18"height="18"v:shapes="_x0000_i1155"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image214.png">的无偏估计量,则常数<imgwidth="12"height="18"v:shapes="_x0000_i1156"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image216.png">等于（）
①
<imgwidth="12"height="37"v:shapes="_x0000_i1157"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image218.png">
②
<imgwidth="12"height="37"v:shapes="_x0000_i1158"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image220.png">
③
2
④
4
【单选题】
对于正态分布<imgwidth="84"height="22"v:shapes="_x0000_i1400"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image525.png">，抽取容量为10的样本，算得样本均值<imgwidth="63"height="20"v:shapes="_x0000_i1401"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image527.png">，样本方差<imgwidth="81"height="20"v:shapes="_x0000_i1402"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image529.png">，给定显著水平<imgwidth="60"height="18"v:shapes="_x0000_i1403"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image531.png">，检验假设<imgwidth="75"height="22"v:shapes="_x0000_i1404"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image533.png"><imgwidth="35"height="22"v:shapes="_x0000_i1405"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image535.png"><imgwidth="58"height="18"v:shapes="_x0000_i1406"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image537.png">.则正确的方法和结论是（）
①
用<imgwidth="12"height="14"v:shapes="_x0000_i1407"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image539.png">检验法，查临界值表知<imgwidth="78"height="22"v:shapes="_x0000_i1408"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image541.png">，拒绝<imgwidth="22"height="22"v:shapes="_x0000_i1409"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image465.png">
②
用<imgwidth="12"height="14"v:shapes="_x0000_i1410"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image539.png">检验法，查临界值表知<imgwidth="75"height="22"v:shapes="_x0000_i1411"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image544.png">，拒绝<imgwidth="22"height="22"v:shapes="_x0000_i1412"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image465.png">
③
用<imgwidth="12"height="14"v:shapes="_x0000_i1413"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image546.png">检验法，查临界值表知<imgwidth="102"height="22"v:shapes="_x0000_i1414"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image548.png">，拒绝<imgwidth="22"height="22"v:shapes="_x0000_i1415"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image465.png">
④
用<imgwidth="12"height="14"v:shapes="_x0000_i1416"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image546.png">检验法，查临界值表知<imgwidth="84"height="22"v:shapes="_x0000_i1417"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image550.png">，拒绝<imgwidth="22"height="22"v:shapes="_x0000_i1418"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image465.png">
【单选题】
设<imgwidth="12"height="14"v:shapes="_x0000_i1185"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image253.png">个随机变量<imgwidth="86"height="22"v:shapes="_x0000_i1186"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image239.png">是独立同分布，<imgwidth="164"height="42"v:shapes="_x0000_i1187"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image255.png"><imgwidth="32"height="20"v:shapes="_x0000_i1188"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image257.png"><imgwidth="115"height="42"v:shapes="_x0000_i1189"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image259.png">，则下列结论中，正确的是（）
①
<imgwidth="12"height="14"v:shapes="_x0000_i1190"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image261.png">是<imgwidth="12"height="12"v:shapes="_x0000_i1191"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image263.png">的无偏估计量
②
<imgwidth="12"height="14"v:shapes="_x0000_i1192"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image261.png">是<imgwidth="12"height="12"v:shapes="_x0000_i1193"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image263.png">的极大似然估计量
③
<imgwidth="12"height="14"v:shapes="_x0000_i1194"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image261.png">是<imgwidth="12"height="12"v:shapes="_x0000_i1195"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image263.png">的极大似然估计量
④
<imgwidth="12"height="14"v:shapes="_x0000_i1196"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image261.png">是<imgwidth="12"height="12"v:shapes="_x0000_i1197"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image263.png">的极大似然估计量
【单选题】
设总体<imgwidth="14"height="14"v:shapes="_x0000_i1114"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image154.png">的分布函数为<imgwidth="32"height="20"v:shapes="_x0000_i1115"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image156.png">,则总体均值<imgwidth="12"height="18"v:shapes="_x0000_i1116"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image158.png">和方差<imgwidth="18"height="20"v:shapes="_x0000_i1117"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image160.png">的矩估计分别为（）
①
<imgwidth="135"height="42"v:shapes="_x0000_i1118"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image162.png">
②
<imgwidth="173"height="40"v:shapes="_x0000_i1119"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image164.png">
③
<imgwidth="186"height="42"v:shapes="_x0000_i1120"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image166.png">
④
<imgwidth="156"height="40"v:shapes="_x0000_i1121"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image168.png">
【单选题】
设某钢珠直径<imgwidth="14"height="14"v:shapes="_x0000_i1251"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image322.png">服从正态分布<imgwidth="49"height="18"v:shapes="_x0000_i1252"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image324.png">，（单位：mm），其中<imgwidth="12"height="18"v:shapes="_x0000_i1253"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">为未知参数，从刚生产出的一大堆钢珠中随机抽出9个，求得样本均值<imgwidth="122"height="49"v:shapes="_x0000_i1254"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image326.png">，样本方差<imgwidth="170"height="40"v:shapes="_x0000_i1255"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image328.png">。则<imgwidth="12"height="18"v:shapes="_x0000_i1256"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image276.png">的极大似然估计值为（）
①
31.06
②
<imgwidth="176"height="20"v:shapes="_x0000_i1257"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image330.png">
③
0.98
④
<imgwidth="58"height="20"v:shapes="_x0000_i1258"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image332.png">
随机题目
【单选题】
消化性溃疡抗Hp的四联疗法正确的是（）。
①
兰索拉唑+阿莫西林+克拉霉素+胶体次碳酸铋
②
兰索拉唑+克拉霉素+甲硝唑+硫糖铝
③
雷尼替丁+阿莫西林+胶体次碳酸铋+甲硝唑
④
西咪替丁+胶体次碳酸铋+哌仑西平+替硝唑
⑤
奥美拉唑+甲硝唑+阿奇霉素+胶体次碳酸铋
【单选题】
符合线槽敷线一般规定的是（ ）。 ①电线在线槽内应有一定余量，不得有接头；②电线按回路编号分段绑扎，绑扎点间距不应大于4m；③同一回路的相线和零线，敷设于同一金属线槽内；④同一路径无电磁兼容要求的配电线路，可敷设于同一金属线槽内。
①
①②③
②
②③④
③
①②③④
④
②③④