spearman与person相关分析对比.ppt
,Spearman 与Pearson,汇报人：屠星月,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,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）：,Rx and Ry are the ranks of the x and y variables,respectively,is the square of the difference between the corresponding ranks of xi and yi,and n is the number observations.,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。,三,Spearman 与Pearson相关分析的对比,三,Spearman 与Pearson相关分析的对比,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 data2.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.,四,结果的解释,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,四,结果的解释,r 的大小,Benedict K，The Correlation Coefficient-Explained in Three Steps，,四,结果的解释,六,参考文献,Sullivan,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-MoreSBenedict K，The Correlation Coefficient-Explained in Three Steps，Amanda Rockinson-Szapkiw，How to Calculate Statistical Power Using SPSS,谢谢！,
