电大【实用卫生统计学】第三次作业答案参考小抄.doc

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1、专业好文档实用卫生统计学行考册作业3答案一、 名词解释1、 四格表资料：两个样本率的资料又称为四格表资料，在四格表资料中连个样本的实际发生频数和实际未发生频数为基本数据，其他数据可由这四个基本数据推算出来。2、 参数检验：是一种要求样本来自总体分布型是已知的（如正态分布），在这种假设的基础上，对总体参数进行统计推断的假设检验。3、 非参数检验：是一种不依赖总体分布类型，也不对总体参数进行统计推断的假设检验。4、 直线相关系数：它是说明具有直线关系的两个变量间，相关关系的密切程度与相关方向的统计指标。相关系数没有单位，取值范围是，r的绝对值越大说明两变量关系越密切5、 完全负相关：这是一种极为特

2、殊的负相关关系，从散点图上可以看出，有x与y构成的散点完全分布在一条直线上，x增加，y相应减少，算得得相关系数r=-1。二、 填空题：1、 n，p，1-p，np，n（1-p）2、 。3、 任何，严重偏态分布的资料，分布不明。4、 散点图，直线相关系数5、 直线相关，直线回归分析三、 选择题1、A 2、D 3、B 4、B 5、D 6、B 7、C 8、B 9、D 10、B四、简答题1、答：数学上的函数关系式y=a+bx,是表示变量x与y是严格意义上的一一对应关系。每一个x值，都会有一个确定并唯一的y值与之对应，在坐标系中，所有的点（x，y）形成一条直线。而统计中的回归式，其因变量是y的估计值，它的

3、数值大小与实际的y值是存在一定差距的。从散点图来看，所有的点(x,y)不是全部落在回归直线上，而只能是围绕七均匀的分布。2、答： 直线回归系数r是说明具有直线关系的两个变量词，相关关系的密切程度与相关方向的统计指标。总体相关系数用表示，样本相关系数用r表示，r是的估计值。相关关系没有单位，取值范围是。r值为正，表示两变量呈正相关，x与y变化趋势是正向的。r的值为负表示两变量呈负相关，x与y呈反向变化，通常r的值越大，表示两变量相关关系越密切。 直线回归系数b即回归直线的斜率，b0表示直线从左下方走向右上方，y随x增大而增大；b0表示直线从左上方走向右下方，y随x增大而减小；b=0则直线与x轴平

4、行，x与y无直线关系。b的统计学意义是x没增（减）一个单位，y平均改变b个单位。3、答：（1）四格表检验的适用条件1）当且所有时，用检验的基本公式或四格表专用公式。2）当但有时，需用四格表检验的校正公式。3）若，或时，需用确切概率计算法。（2）配对资料卡方检验适用于同一实体对象实验前后比较、同一样本用两种方法检验以及配对的两个受试对象接受两种不同处理等。当时需用校正公式。(3)行列表资料的卡方检验适用条件：不宜有1/5以上格子数的理论频数小于5，或有1个格子的理论数小于1.4、答：区别在于：（1）参数检验要求样本来自正态总体，而非参数检验则不对总体分布有任何要求；（2）参数检验是对总体参数（如

5、总体均数）进行的检验，而非参数检验考察的是总体的分布情况。 参数检验的优点是能充分利用所提供的信息，检验效率较高。缺点是对样本所对应的总体分布有比较严格的要求，因此适用资料有限。非参数检验的优点是不受总体分布类型的限制，适用于任何分布的资料。其缺点是不直接对原始数据作检验，从而有可能会损失信息并降低其检验效率。5、答：（1）计数资料可进行总体率的参数估计及样本率（或构成比）比较的假设检验（2）计量资料可进行总体均数的参数估计，样本均数比较的假设检验，秩和检验，直线相关分析和直线回归分析等（3）等级资料可进行等级资料秩和检验，等级相关检验等。6、答：（1）建立检验假设差值总体中位数为0差值总体中

6、位数不为0（2）计算统计量T依差值的绝对值从小到大编秩，并按差值的正负分列两栏。编秩时遇差值为0，则舍去不予编秩，同时在总秩序中要相应减去零的个数。如果遇到绝对值相等的差值时，对符号相同且绝对值相等的差值顺序编秩，符号相反且绝对值相等的差值取平均秩次，再在秩次之前带上原差值的正负号。编完秩次后分别求正负秩次总和，取绝对值最小者为检验统计量T。（3）确定P值和做出统计结论（查附表5）五、计算题1、(1)计数资料；是四个表资料；四个基本数据是（2）宜用四格表检验方法。适用条件见教材100页。（3）由于患者未患病新21618旧112132133750由于，所以15,宜用校正公式7.6，v=（2-1）

7、（2-1）=12.140.05尚不能认为两组工人皮炎患病率有差别。2、（1）完全随机设计；计量型（2）t检验，方差分析要求样本来自于正态分布，且两总体方差相等。 完全随机设计秩和检验对分布无要求。（3）铅作业工人（1） 秩次 非铅作业（2） 秩次 1.05 12 0.34 3 0.97 11 0.22 1 1.35 16 0.54 5 0.89 9 0.54 6 1.87 20 0.29 2 1.56 19 0.56 7 1.34 15 0.45 4 1.22 14 0.76 8 1.38 17 0.94 10 1.45 18 1.10 13 T1=151 T2=59 ，所以T=59，查表，可

8、得范围是78132所以P0.05,即两组工人的血铅含量不同。3、（1）计量资料；配对设计（2）配对t检验差值服从正态分布配对设计的符号秩和检验对分布无要求（3），N=10，查表，得T的范围是847，T=0不在范围847内，所以消毒前后没升水中的细菌总数有差别。Winger Tuivasa-Sheck, who scored two tries in the Kiwis 20-18 semi-final win over England, has been passed fit after a lower-leg injury, while Slater has been named at fu

9、ll-back but is still recovering from a knee injury aggravated against USA.Both sides boast 100% records heading into the encounter but Australia have not conceded a try since Josh Charnleys effort in their first pool match against England on the opening day.Aussie winger Jarryd Hayne is the competit

10、ions top try scorer with nine, closely followed by Tuivasa-Sheck with eight.But it is recently named Rugby League International Federation player of the year Sonny Bill Williams who has attracted the most interest in the tournament so far.The Kiwi - with a tournament high 17 offloads - has the chanc

11、e of becoming the first player to win the World Cup in both rugby league and rugby union after triumphing with the All Blacks in 2011.Id give every award back in a heartbeat just to get across the line this weekend, said Williams.The (lack of) air up there Watch mCayman Islands-based Webb, the head

12、of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about how he felt and I w

13、ould like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investigation into the refe

14、rees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunda.The weather plays an importa

15、nt role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather

16、lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbule

17、nce.The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.They blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the Kiwis in Manches

18、ter.Five years ago they cruised through to the final and so far history has repeated itself here - the last try they conceded was scored by Englands Josh Charnley in the opening game of the tournament.That could be classed as a weakness, a team under-cooked - but I have been impressed by the Kangaro

19、os focus in their games since then.They have been concentrating on the sort of stuff that wins you tough, even contests - strong defence, especially on their own goal-line, completing sets and a good kick-chase. Theyve been great at all the unglamorous stuff that often goes unnoticed in the stands b

20、ut not by your team-mates.It is as though their entire tournament has been preparation for the final.In Johnathan Thurston, Cooper Cronk, Cameron Smith and either Billy Slater or Greg Inglis at full-back they have a spine that is unmatched in rugby league. They have played in so many high-pressure g

21、ames - a priceless asset going into Saturday.The Kiwis are a lot less experienced but winning a dramatic match like their semi-final against England will do wonders for their confidence.They defeated Australia in the Four Nations final in 2010 and the last World Cup, and know they can rise to the big occasion.