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举一反三
- <img src="http://img1.ph.126.net/xRWXQUfZJwmSXkQiZ0l2HQ==/3826089358528721080.jpg" />? <img src="http://img2.ph.126.net/QX-jBzzFTrwpTjQkcBtfcg==/2449958197307439176.jpg" />|<img src="http://img0.ph.126.net/3XApesgU0Iga8L5Tkm0YXg==/6630324495838409649.jpg" />|<img src="http://img2.ph.126.net/sPsiWYSStdIbrCUcsMBK9A==/3114802092298176869.jpg" />|<img src="http://img1.ph.126.net/y-FdOVmaocQvOIOXtXTxEw==/662592095194801258.jpg" />
- <img src="http://img1.ph.126.net/JMg9tqo6gf8sEot0y9NSUg==/6619559177490984445.gif" />? 0|<img src="http://img1.ph.126.net/uSXYTJKY1--cmM46BmL7Pg==/1177972777551495010.gif" />|<img src="http://img0.ph.126.net/-vDBDVZEQJqbFun7PrX7vg==/2887370311115280318.gif" />|<img src="http://img2.ph.126.net/NK1mnxUZa_ibCGqQvHOaoQ==/2435884448470832003.gif" />
- 心形线 <img src="http://img1.ph.126.net/51iXNdllu1oPmo73M33A-g==/3828059683365171853.png" /> ， 其中 <img src="http://img1.ph.126.net/l1SGfBOzwcoKTuLZSsBGJQ==/2695685851975900600.png" />， 则该心形线的弧长等于 （;; ）? <img src="http://img2.ph.126.net/Z2kfcGdQYGVls8Ce891a9w==/1419196832675449814.png" />|<img src="http://img2.ph.126.net/4jCSzt215P9escwFQA6wzg==/6619425037072595432.png" />|<img src="http://img1.ph.126.net/L43F-slSm-WU9DuF-i0ZXg==/3228517982971533103.png" />|<img src="http://img1.ph.126.net/J3Pcx4QQxPm779wQddVKQA==/1047649863334615897.png" />
- <img src="http://img0.ph.126.net/q6tqn77YyTg_j7CabeHYJw==/3109735542717391842.jpg" />? <img src="http://img1.ph.126.net/QO3FWMGgxAVtN31l0ulKFw==/6619487709235793443.jpg" />|<img src="http://img2.ph.126.net/-x9WCwFJKaqmfOJLJjH0_Q==/6630623563001319953.jpg" />|<img src="http://img1.ph.126.net/5eiGUQZYA2gEX9q4m57n4Q==/6608642126539334311.jpg" />|<img src="http://img1.ph.126.net/YixVkAU6iexb7xitW-q8Lg==/6630125484233816848.jpg" />
- 设总体X～N(μ,σ^2),μ和σ是未知参数。为估计参数σ^2的置信区间，应选T=____________作为枢轴变量,并且T服从______。? <img src="http://img2.ph.126.net/SHUrsWncVzw3TbqMT630Ug==/6632510324955921443.png" /><br />|<img src="http://img2.ph.126.net/I5VmIURcDfhDZIPIQy5JZw==/6632334403095483329.png" />|<img src="http://img0.ph.126.net/v1kDLV9rE4i9IWRPugufXQ==/6632404771839652521.png" />|<img src="http://img0.ph.126.net/sQOy3VhGtuk-bcM7dsC3kQ==/6632272830444326010.png" />