A、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/b4b33286-c7ac-45ea-b71b-b5435c2daa40.jpg" width="95" height="23" />
B、若<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/2d3aa8a4-3c8a-4f30-9bbc-5badf124ca3b.jpg" width="96" height="27" />，则<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/de3ea2f9-c681-4114-8a60-430b7256a059.jpg" width="13" height="28" />比<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/129edb74-af81-4e6f-ad58-442e62e706af.jpg" width="15" height="27" />更有效
C、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/62c5f04d-d2b3-4f54-b019-8bc1d7a4a7d9.jpg" width="199" height="34" />
D、若a，b为常数，并且a+b=1=1，则<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/0420f268-98d8-40f7-bf08-ce955983db28.jpg" width="74" height="27" />也是θ的无偏估计量
E、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/558e142a-a01e-4999-adbe-3c625c07e185.jpg" width="17" height="26" />和<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/1610c5e6-903e-4404-bbcf-3778fed5298e.jpg" width="29" height="36" />是θ的无偏估计量
查看答案
，
都是总体参数θ的无偏估计量，下列说法中正确的有（ ）。