STATA软件操作(六)综合实例分析

完全随机设计资料例1

研究烫伤后不同时期切痂对肝脏三磷酸腺苷（ATP）含量的影响，将30只雄性大鼠随机分3组,每组10只：

A组烫伤对照组；B组烫伤后24小时(休克期)切痂组；C组烫伤后96小时（非休克期）切痂组。全部动物统一在烫伤后168小时处死并测量其肝脏的ATP含量。三组大鼠肝脏的ATP含量有无差别？第一页，共49页。A组B组C组

7.76

11.14

10.85

7.71

11.60

8.58

8.43

11.42

7.19

8.47

13.85

9.36

10.30

13.53

9.59

6.67

14.16

8.81

11.73

6.94

8.22

5.78

13.01

9.95

6.61

14.18

11.26

6.97

17.72

8.68表1

大鼠烫伤后肝脏ATP含量的测量结果（单位：mg）第二页，共49页。命令将数据拷到dataeditorstackvar1var2var3,into(x)rename_stackgrouponewayxgroup,tabsch第三页，共49页。onewayxgroup,tabsch|Summaryofxgroup|MeanStd.Dev.Freq.------------+------------------------------------1|8.04300011.8080747102|12.7552.7900466103|9.24900011.224277110------------+------------------------------------Total|10.0156672.833314930AnalysisofVarianceSourceSSdfMSFProb>F------------------------------------------------------------------------Betweengroups119.831385259.915692714.320.0001Withingroups112.971139274.18411624------------------------------------------------------------------------Total232.802524298.02767324Bartlett'stestforequalvariances:chi2(2)=5.5965Prob>chi2=0.061Comparisonofxbygroup(Scheffe)RowMean-|ColMean|12---------+----------------------2|4.712|0.000|3|1.206-3.506|0.4310.003第四页，共49页。结果解释

烫伤后不同时期切痂对肝脏三磷酸腺苷（ATP）含量不同（F＝14.32，P<0.0001）,烫伤后24小时(休克期)切痂组ATP含量高于其他两组，烫伤对照组与烫伤后96小时（非休克期）切痂组ATP含量差别无统计学意义。第五页，共49页。随机区组设计资料【例2】

为研究注射不同剂量雌激素对大白鼠子宫重量的影响，取4窝不同种系的大白鼠（b=4），每窝3只，随机地分配到3个组内(k=3)接受不同剂量雌激素的注射，然后测定其子宫重量，结果见表2。问注射不同剂量的雌激素对大白鼠子宫重量是否有影响？第六页，共49页。大白鼠种

类雌激素剂量(ug/100g)A106116145B4268115C70111133D426387表2

大白鼠注射不同剂量雌激素后的子宫重量(g)第七页，共49页。数据格式第八页，共49页。anovaxblockdoseNumberofobs=12R-squared=0.9584RootMSE=9.51607AdjR-squared=0.9238Source|PartialSSdfMSFProb>F-----------+----------------------------------------------------Model|12531.666752506.3333327.680.0004|block|6457.6666732152.5555623.770.0010dose|60742303733.540.0006|Residual|543.333333690.5555556-----------+----------------------------------------------------Total63636第九页，共49页。结果解释可以看出，区组因素和实验因素差别有统计学意义。注射不同剂量的雌激素对大鼠子宫重量有影响（F＝33.54，P＝0.0010）。第十页，共49页。例3某医师将20名失眠患者随机等分为两组，一组服用安眠药，另一组服用安慰剂，研究者要评价某安眠药的催眠效果，治疗失眠前后的睡眠时间及其差值结果见表3，试作统计分析。第十一页，共49页。表3安眠药组安慰剂组序号前后差数序号前后差数44.05.61.853.96.00.973.05.22.292.84.01.2第十二页，共49页。组别例数疗前疗后疗前比较tP安眠药组安慰剂组组别例数差值组内疗效组间疗效比较

tPtP安眠药组安慰剂组第十三页，共49页。数据格式第十四页，共49页。命令sktestt1t2ifgroup==1sktestt1t2ifgroup==2sdtestt1,by(group)ttestt1,by(group)ttestt1=t2ifgroup==1ttestt1=t2ifgroup==2gend=t2-t1sdtestd,by(group)ttestd,by(group)第十五页，共49页。ttestt1,by(group)Two-samplettestwithequalvariances------------------------------------------------------------------------------Group|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+--------------------------------------------------------------------1|103.45.1808929.57203343.0407923.8592082|103.32.2009975.63560992.8653123.774688---------+--------------------------------------------------------------------combined|203.385.1324416.5922973.1077963.662204---------+--------------------------------------------------------------------diff|.13.2704112-.4381129.6981129------------------------------------------------------------------------------diff=mean(1)-mean(2)t=0.4807Ho:diff=0degreesoffreedom=18Ha:diff<0Ha:diff!=0Ha:diff>0Pr(T<t)=0.6818Pr(|T|>|t|)=0.6365Pr(T>t)=0.3182第十六页，共49页。ttestt1=t2ifgroup==1

Pairedttest------------------------------------------------------------------------------Variable|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+--------------------------------------------------------------------t1|103.45.1808929.57203343.0407923.859208t2|105.02.2563851.81076094.4400165.599983---------+--------------------------------------------------------------------diff|10-1.57.1903505.6019413-2.000603-1.139397------------------------------------------------------------------------------mean(diff)=mean(t1-t2)t=-8.2479Ho:mean(diff)=0degreesoffreedom=9Ha:mean(diff)<0Ha:mean(diff)!=0Ha:mean(diff)>0Pr(T<t)=0.0000Pr(|T|>|t|)=0.0000Pr(T>t)=1.0000第十七页，共49页。ttestt1=t2ifgroup==2Pairedttest------------------------------------------------------------------------------Variable|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+--------------------------------------------------------------------t1|103.32.2009975.63560992.8653123.774688t2|104.96.2638181.83426614.3632025.556798---------+--------------------------------------------------------------------diff|10-1.64.168127.5316641-2.02033-1.25967------------------------------------------------------------------------------mean(diff)=mean(t1-t2)t=-9.7545Ho:mean(diff)=0degreesoffreedom=9Ha:mean(diff)<0Ha:mean(diff)!=0Ha:mean(diff)>0Pr(T<t)=0.0000Pr(|T|>|t|)=0.0000Pr(T>t)=1.0000第十八页，共49页。ttestd,by(group)Two-samplettestwithequalvariances------------------------------------------------------------------------------Group|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+--------------------------------------------------------------------1|101.57.1903505.60194131.1393972.0006032|101.64.168127.53166411.259672.02033---------+--------------------------------------------------------------------combined|201.605.1238579.55390961.3457621.864238---------+--------------------------------------------------------------------diff|-.07.2539685-.6035681.463568------------------------------------------------------------------------------diff=mean(1)-mean(2)t=-0.2756Ho:diff=0degreesoffreedom=18Ha:diff<0Ha:diff!=0Ha:diff>0Pr(T<t)=0.3930Pr(|T|>|t|)=0.7860Pr(T>t)=0.6070第十九页，共49页。综合分析结论服药前两组具有可比性（P=0.637）；服用安眠药和安慰剂均有延长睡眠时间的效果(P<0.001；P<0.001)；服用安眠药与服用安慰剂平均延长的睡眠时间差别无统计学意义(P＝0.786)；即安眠药无效。第二十页，共49页。例4对一组胃癌病人先后用两种泌酸刺激剂，然后分别测定其最大酸排量(mEq/h)，以分析两药的效果，第二十一页，共49页。对21名胃癌病人先后用两种泌酸刺激剂，然后分别测定其最大酸排量(mEq/h)，以分析两药的效果。id加大组织胺X五肽胃泌素YX-Y110.518.841.67212.0510.491.56322.2620.281.9843.111.781.3352.031.760.2764.613.850.7671.230.910.3282.532.040.4993.962.990.97104.683.920.761111.769.931.831214.5612.492.07139.468.041.421411.29.441.761516.5314.122.41168.056.671.38174.543.870.67189.227.931.29196.084.921.16208.657.521.132113.9211.931.99平均8.627.321.30第二十二页，共49页。ttestx=yPairedttest------------------------------------------------------------------------------Variable|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+--------------------------------------------------------------------x|218.6161911.1823515.4182156.14984911.08253y|217.321.0665764.8876655.0951619.544839---------+--------------------------------------------------------------------diff|211.296191.1318088.60402391.0212421.571139------------------------------------------------------------------------------mean(diff)=mean(x-y)t=9.8339Ho:mean(diff)=0degreesoffreedom=20Ha:mean(diff)<0Ha:mean(diff)!=0Ha:mean(diff)>0Pr(T<t)=1.0000Pr(|T|>|t|)=0.0000Pr(T>t)=0.0000第二十三页，共49页。regyxSource|SSdfMSNumberofobs=21-------------+------------------------------F(1,19)=6021.70Model|476.2826241476.282624Prob>F=0.0000Residual|1.5027922419.079094328R-squared=0.9969-------------+------------------------------AdjR-squared=0.9967Total|477.7854162023.8892708RootMSE=.28124------------------------------------------------------------------------------y|Coef.Std.Err.tP>|t|[95%Conf.Interval]--------+----------------------------------------------------------------x|.9006605.011606577.600.000.8763678.9249532_cons|-.4402625.1173336-3.750.001-.6858445-.1946806------------------------------------------------------------------------------第二十四页，共49页。五肽胃泌素与加大组织胺的最大排酸量的线性回归五肽胃泌素，y

加大组织胺，X051015202505101520graphyyhatx,c(.l)s(oi)xlabel(0(5)25)ylabel(0(5)20)predictyhat第二十五页，共49页。分析思路：配对t检验：,Sd=0.6040,t=9.8339,P<0.0001差值的95％CI：1.02~1.57(mEq/h)回归分析回归系数的95％CI：0.88~0.92。第二十六页，共49页。结论：胃癌病人用加大组织胺后的最大排酸量比五肽胃泌素平均多1.30(95%CI:1.02~1.57)mEq/h；回归分析显示，五肽胃泌素的最大排酸量是加大组织胺的90％(95%CI:88%~92%)。第二十七页，共49页。例5:某地方病研究中，用两种食物配方饲养大白鼠，测量其固定部位的心肌切片坏死面积，并以显微镜下占有格子数表达其严重程度，结果见表4，试分析二组间的差异。第二十八页，共49页。第二十九页，共49页。分析思路首先，看作定量资料，采用成组设计的t检验比较组间差别其次，将定量资料转化为定性资料，比较两组心肌坏死率最后，视为等级资料，采用Wilcoxon秩和检验比较两组心肌坏死严重程度的等级分布第三十页，共49页。分析结果定量分析

定量分析结果显示：两组心肌坏死面积差别无统计学意义。

第三十一页，共49页。定性分析2=2.108，P=0.147。定性分析结果显示：两组心肌坏死率差异亦无统计学意义。第三十二页，共49页。等级比较u=2.119，P=0.034等级比较结果显示：两组心肌坏死严重程度的等级分布差别有统计学意义。结合实例，可见甲组心肌坏死程度较严重。第三十三页，共49页。资料类型的转换定量资料→等级资料→定性资料转换过程是一个信息递减的过程第三十四页，共49页。例6将人的血滤液放置不同时间，测定其血糖浓度。放置时间分4种(0,45,90,135分钟)，取八个健康人的血液，各分成4份，按配伍组设计，结果见下表。受试者编号放置时间合计0459013519595898336229594888436131061059790398498979590380510298978838561121121019441971051039788393895929080357合计8087967546973055平均10199.594.387.1－标准差6.326.74.684.52

第三十五页，共49页。数据格式第三十六页，共49页。anovaxtimeidNumberofobs=32R-squared=0.9541RootMSE=2.00186AdjR-squared=0.9323Source|PartialSSdfMSFProb>F-----------+----------------------------------------------------Model|1749.812510174.9812543.660.0000|time|943.593753314.5312578.490.0000id|806.218757115.17410728.740.0000|Residual|84.15625214.00744048-----------+----------------------------------------------------Total|1833.968753159.1602823第三十七页，共49页。配伍组设计的方差分析变异来源SSdfMSFPtime943.63314.578.490.000id806.27115.228.740.000Residual84.16214.007Total18343159.16

第三十八页，共49页。血滤液的放置时间与血糖浓度的关系

085血糖浓度，mg%放置时间，分45901359095100105第三十九页，共49页。结论：人血滤液中的血糖浓度在放置0～135分钟期间，随时间的延长而下降，起初下降不明显，而后逐渐加快，成指数下降。第四十页，共49页。完全随机设计资料的分析

与多重回归分析t检验与回归的关系方差分析与回归分析第四十一页，共49页。例7t检验与回归的关系正常人组II期矽肺组64.2674.9742.8488.0652.4893.4748.1995.1080.22100.6769.61101.1418.19113.5250.90正常人与矽肺患者血清粘蛋白合理(mg/100mg)第四十二页，共49页。资料重新整理

ygroup1.64.2602.42.8403.52.4804.48.1905.80.2206.69.6107.18.1908.50.909.74.97110.88.06111.93.47112.95.1113.100.67114.101.14115.113.521第四十三页，共49页。t检验结果.ttesty,by(group)Two-samplettestwithequalvariances----------------------------------------------------------------------------Group|ObsMeanStd.Err.Std.Dev.[95%Conf.Interval]---------+------------------------------------------------------------------0|853.336256.66210218.8432737.5828869.089621|795.275714.53563112.0001584.17742106.374---------+------------------------------------------------------------------combined|1572.9086.87165826.6138258.1697687.64624---------+------------------------------------------------------------------diff|-41.939468.307497-59.88672-23.99221----------------------------------------------------------------------------Degreesoffreedom:13Ho:mean(0)-mean(1)=diff=0Ha:diff<0Ha:diff~=0Ha:diff>0t=-5.0484t=-5.0484t=-5.0484P<t=0.0001P>|t|=0.0002P>t=0.9999第四十四页，共49页。与方差分析结果等价.anovaygroupNumberofobs=15R-squared=0.6622RootMSE=16.0516AdjR-squared=0.6362Source|PartialSSdfMSFProb>F-----------+----------------------------------------------------Model|6566.6291816566.6291825.490.0002|group|6566.6291816566.6291825.490.0002|Residual|3349.5038913257.654145-----------+---