医学统计学英文课件-LinearCorrelationRe.pptVIP

Lesson OneBasic concepts of medical statistics and an introduction to SPSS School of Public Health Sun Yat-Sen University 3. Does the linear correlation coefficient change if we change the unit of X or Y? What about the linear regression equation ? 4. What are the steps for linear correlation analysis? Why is the scatter plot necessary? 5. What’s the meaning of least square method ? 100 120 140 160 180 200 220 100 120 140 160 180 200 220 Father’s height（cm） Son’s height (cm) 6. When should we analyze the data by rank correlation? It is useful to: ranked data As well as measurement data ---- not follow a normal distribution; or not sure about the distribution; or not precisely measured or X or Y is an ordinal variable 7. Assume the regression equation of height of pupil Y (m) on age X (year) is  =0.5+0.07X, is it correct that the average height of 20-year-old individuals should be 1.90m? 8. Is the statement correct that the population regression coefficientβ=0 if the population correlation coefficient ρ=0? 9. X and Y follow a bi-variate（双变量） normal distribution, their linear correlation coefficient r is quite near to 0. A hypothesis test for shows that P 0.90. What is the proper conclusion that we can draw? _________.A. There exists linear relationship between X and Y B. There exists curvilinear(曲线的) relationship between X and YC. There is no linear relationship between X and YD. There isn’t any form of relationship between X and YE. None of the above  * * * * * * * * * * * * * * * * * * * * * * * Lesson Eight Simple Linear Correlation Regression 作业中的问题 统计学描述？ 根据数据特征（本章中设计类型、样本量等）选用的方法？ 正确判断研究设计类型：独立样本？配对样本？ 建立假设的时候就决定单侧还是双侧，而不是在计算时决定； 如第10题中，根据实际情况可以知道使用了增敏剂会有一个正向的效应，故我们选择单侧检验。若使用双侧检验，则认为增敏剂可能有负向效应。两种态度是有区别的。 注意卡方检验中，掌握不同样本量时相应方法的选用（不校正、校正、确切概率法）； 结论要完整，统计学结论+专业结论，P0.05，拒绝H0 ，认为两组的差别有统计学意义，同时，把结论落到“单侧”上来-城市儿童阳性率高于农村儿童。 To understand the definition a