spearman与person相关分析对比.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,Spearman,与,Pearson,汇报人：屠星月,1,内容,Spearman,相关系数的含义,Spearman,相关分析的特点,Spearman,与,Pearson,相关分析的对比,结果的解释,对我的研究数据的适用性,2,一,Spearman,相关系数的含义,Spearman rank-order correlation coefficient,两个连续或等级,/,秩变量之间的单调,相关（,monotone association,）,关系。,单调函数描述两个变量之间的关系的程度,（,how well the relationship between two variables can be described using a monotonic function,）,Pearson,相关系数的一个特例（系数计算中的,X,Y,被其秩代替）：,R,x,and R,y,are the ranks of the x and y variables,respectively,is the square of the difference between the corresponding ranks of,x,i,and,y,i,and n is the number observations.,3,二,Spearman,相关分析的特点,不对变量的分布做假设,：,非参数（自由分布）,可用于等级数据（,ordinal data,：,The most fundamental requisite is to be able to measure our observed correspondence by,a plain numerical symbol,）,当数据分布导致，,pearson,相关系数不适用或者产生误导的使用。,when the distribution of data makes Pearsons correlation coefficient undesirable or misleading,当数据为定性的变量，或者含有异常值时尤其适用。,4,三,Spearman,与,Pearson,相关分析的对比,5,三,Spearman,与,Pearson,相关分析的对比,6,三,Spearman,与,Pearson,相关分析的对比,1.,对同样的数据，,Spearman,相关统计相关，而,pearson,可能显著也可能不显著,the significance of Spearmans correlation can lead to the significance or non-significance of Pearsons correlation coefficient even for big sets of data,2.,对同样的数据，二者所得的相关系数符号有可能不一样,（,It is possible to meet a situation where Pearsons coefficient is negative while Spearmans coefficient is positive.,）,3.,注意：确保不要针对两个变量的相关强度，对,spearman,相关系数过度解释,Make sure not to overinterpret Spearmans rank correlation coefficient as a significant measure of the strength of the associations between two variables.,7,四,结果的解释,Effect Size(Biological relevance/correlation coefficient/r,),Statistical significance(P),两个变量一起变化的强度和方向,Extent to which two variables tend to change together(strength and direction),Statistical power,8,四,结果的解释,r,与,P,值,呈现分析结果时应当包含的信息,当统计显著，但相关系数不大，则有可能是其他变量的影响,9,四,结果的解释,r,的大小,Benedict K,，,The Correlation Coefficient-Explained in Three Steps,，,G.M.and R.Feinn(2012).Using effect size-or why the P value is not enough.,Journal of graduate medical education,4(3):279-282.,Support,M.E.A comparison of the Pearson and Spearman correlation methods.“,Hauke,J.and T.Kossowski(2011).Comparison of values of Pearsons and Spearmans correlation coefficients on the same sets of data.,Quaestiones geographicae,30(2):87-93.,Martinez-Abrain,A.(2008).Statistical significance and biological relevance:A call for a more cautious interpretation of results in ecology.,acta oecologica,34(1):9-11.,Power of a Statistical Test-MoreS,Benedict K,，,The Correlation Coefficient-Explained in Three Steps,，,Rockinson-Szapkiw,，,How to Calculate Statistical Power Using SPSS,，