设总体<imgwidth="86"height="22"v:shapes="_x0000_i1257"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image373.png">,其中<imgwidth="35"height="22"v:shapes="_x0000_i1258"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image375.png">已知,<imgwidth="86"height="22"v:shapes="_x0000_i1259"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image377.png"><imgwidth="46"height="18"v:shapes="_x0000_i1260"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image379.png">为来自总体<imgwidth="14"height="12"v:shapes="_x0000_i1261"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image341.png">的样本,<imgwidth="14"height="18"v:shapes="_x0000_i1262"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image382.png">为样本均值,<imgwidth="12"height="20"v:shapes="_x0000_i1263"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image384.png">为样本方差,则下列统计量中服从<imgwidth="9"height="18"v:shapes="_x0000_i1264"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image386.png">分布的是()
①
<imgwidth="75"height="69"v:shapes="_x0000_i1265"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image388.png">
②
<imgwidth="75"height="69"v:shapes="_x0000_i1266"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image390.png">
③
<imgwidth="75"height="73"v:shapes="_x0000_i1267"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image392.png">
④
<imgwidth="53"height="86"v:shapes="_x0000_i1268"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image394.png">