点估计的优良准则有哪些？

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点估计的优良准则有哪些？

答案

参考答案：

①无偏性；②一致性；③有效性

完形填空

We often talk about ourselves as if we have permanent genetic defects （缺陷） that can never be changed. “I’m impatient.” “I’m always behind.” “I always put things 36 !” You’ve surely heard them. Maybe you’ve used them to describe 37 .
These comments may come from stories about us that have been 38 for years—often from 39 childhood. These stories may have no 40 in fact. But they can set low expectations for us. As a child, my mother said to me, “Marshall, you have no mechanical （操作机械的） skills, and you will never have any mechanical ski

lls for the rest of your life.” How did these expectations 41 my development? I was never 42 to work on cars or be around 43 . When I was 18, I took the US Army’s Mechanical Aptitude Test. My scores were in the bottom for the entire nation!
Six years later,   44 , I was at California University, working on my doctor’s degree. One of my professors, Dr. Bob Tannbaum, asked me to write down things I did well and things I couldn’t do. On the positive side, I 45 down, “research, writing, analysis, and speaking.” On the 46 side, I wrote, “I have no mechanical skills.”
Bob asked me how I knew I had no mechanical skills. I explained my life 47  and told him about my 48 performance on the Army test. Bob then asked, “ 49 is it that you can solve 50 mathematical problems, but you can’t solve simple mechanical problems?”
Suddenly I realized that I didn’t   51 from some sort of genetic defect. I was just living out expectations that I had chosen to 52 . At that point, it wasn’t just my family and friends who had been   53  my belief that I was mechanically hopeless. And it wasn’t just the Army test, either. I was the one who kept telling myself, “You can’t do this!” I realized that as long as I kept saying that, it was going to remain true. 54 , if we don’t treat ourselves as if we have incurable genetic defects, we can do well in almost 55 we choose.

小题7:A hoped B. demanded C. encouraged D. agreed

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综合题

从秦至清初，上下两千余年间，北方地区的游牧民族诸如匈奴.突厥.蒙古.契丹.满洲等对国家的统一有重要的影响，历代王朝在这一地区采用多种措施加强统治。阅读下列材料：

材料一后秦灭六国，而始皇帝使蒙恬将十万之众北击胡，悉收河南地。因河为塞，筑四十四县城临河，徙适戍以充之。而通直道，自九原至云阳，因边山险巉溪谷可缮者治之，起临洮至辽东万余里。

——《史记·匈奴列传》

材料二夷狄亦人耳，其情与中原不殊。人主患德泽不加，不必猜忌异类。盖德泽洽，则四夷可使如一家；猜忌多，则骨肉不免为仇敌……突厥贫弱，吾收而养之，计其感恩，入于骨髓，岂肯为患！

——《资治通鉴》卷一九七

材料三康熙五十三年(1714年)写的《溥仁寺碑文》中说:“柔远能迩，自古难之。我朝祖功宗德，远服要荒；深仁厚泽，沦及骨髓。蒙古部落，三皇不治，五帝不服，今已中外无别矣”。

——《避暑山庄和外八庙碑文辑》

请回答：

(1)据材料一，秦始皇时期加强对匈奴地区的管辖采取了哪些措施？（2分）

(2)据材料二反映了其什么样的民族观？结合所学，唐太宗采取了哪些方式“收养”突厥？对当时的中国产生什么影响？（4分）

(3)据材料三并结合所学，康熙帝对蒙古地区是如何加强管辖的？起到了什么作用？（4分）

(4)综合上述材料，你对历代王朝都加强对北方少数民族的统治有何认识？（2分）

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