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