相关与回归资料统计分析中的错误

相关与回归资料统计

分析中的错误实例杜丽娜文章题目及出处西水地区旱獭鼠疫流行时某些指标的相互关系地方病通报2001年8月第16卷第3期原先的设计资料统计方法结果与结论在喜马拉雅旱獭鼠疫自然疫源地，蚤在鼠疫的传播中起到重要作用。作者针对该地区1982-1999年所获监测资料，以旱獭密度，体蚤指数，洞干蚤指数同鼠疫菌检出量进行相关回归统计处理，结果见表1，2，3。表1旱獭密度与动物媒介

检菌量相关比较时间密度(X)检菌量(Y)X2Y2XY19820.37260.13696769.6219830.590.25814.519840.6120.372141.1219850.6490.4096815.7619860.660.36363.619870.48150.23042257.219880.3170.0961492.1219890.3400.11560019900.42004770.2209493.819920.2700.07290019930.470.16492.819940.39003520.122540.719960.3730.136991.1119970.3100.09610019980.0610.0003610.0619990.0520.0002540.1R=0.2763P>0.01表2旱獭体蚤指数与动物媒介

检菌量的相关统计时间密度（X)检菌量（Y）198210.12619838.2919847.4219854.3919865.76198731519886.3719896.9019902.1019915.3719927.4019937.9719942.8019958.2219966319974.3019980.06119990.052r=0.396,p>0.01表3旱獭洞干蚤指数与动物昆虫

检菌量的相关分析时间密度（x)检菌量(y)19820.352619830.33919840.08219850.19619860.07919870.241519880.28719890.04019900.1019910.05719920.04019930.35719940.05019950.04219960.04319970.04019980.02119990.012R=0.7601P<0.01原作者分别对三张表进行相关分析，得到结果是：旱獭密度，体蚤指数与检出量在年度上呈正相关，但并不存在显著差异。但是洞干蚤指数与检出量呈正相关且具统计学意义。对过失的分析原作者目的在于研究动物媒介检菌量与旱獭密度，体蚤指数，洞干蚤指数之间的相关性，应该用多元线性回归进行研究。正确统计分析过程将动物检菌量〔y〕对旱獭密度〔x1),体蚤指数〔x2〕，洞干蚤指数(x3)进行多元线性回归。可以通过共线性诊断来发现自变量之间是否有较强的线性关系，用SAS运行结果如下。TheSASSystemParameterEstimatesParameterStandardTforH0:VariableDFEstimateErrorParameter=0Prob>|T|INTERCEP1-0.8312513.57481227-0.2330.8195X112.1797298.998512520.2420.8121X210.1674710.548319450.3050.7645X3135.13495212.520215372.8060.0140

CollinearityDiagnosticsConditionVarPropVarPropVarPropVarPropNumberEigenvalueIndexINTERCEPX1X2X313.510061.000000.00910.00850.01090.021520.309133.369650.06660.03620.00200.817330.108775.680690.14140.10010.98600.148440.072036.980680.78290.85520.00110.0127TheSASSystem

CollinearityDiagnostics(interceptadjusted)ConditionVarPropVarPropVarPropNumberEigenvalueIndexX1X2X311.816171.000000.12950.14400.135820.689751.622680.71310.01370.409930.494081.917260.15740.84230.4543

StepwiseProcedureforDependentVariableYStep1VariableX3EnteredR-square=0.67726611C(p)=-0.72776750DFSumofSquaresMeanSquareFProb>FRegression1858.77342419858.7734241935.670.0001Error17409.2265758124.07215152Total181268.00000000ParameterStandardTypeIIVariableEstimateErrorSumofSquaresFProb>FX340.318001146.75020790858.7734241935.670.0001Boundsonconditionnumber:1,1-----------------------------------------------------------------------------