交叉验证.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,*,*,交 叉 验 证,以,cars,数据为例,attach(cars),head(cars),summary(lm(distspeed,cars),n-nrow(cars),s-sample(1:n,round(n/2),traindata-carss,testdata-cars-s,summary(lm.tr-lm(distspeed,traindata),ptedist.lm-predict(lm.tr,testdata),ptrdist.lm-predict(lm.tr,traindata),temse-sum(ptedist.lm-testdata$dist)2/nrow(testdata),trmse-sum(ptrdist.lm-traindata$dist)2/nrow(traindata),nls.tr-nls(log(dist)xmid*log(speed),data=traindata,start=list(xmid=0),nls.tr-nls(log(dist)log(xmid*speed),data=traindata,start=list(xmid=0.1),summary(nls.tr),ptedist.nls-predict(nls.tr,testdata),ptrdist.nls-predict(nls.tr,traindata),temse-sum(ptedist.nls-testdata$dist)2/nrow(testdata),trmse-sum(ptrdist.nls-traindata$dist)2/nrow(traindata),训练集合测试集交换,