llawboot.samp<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) { llawboot.samp[,i]<-sample(law[,1],15,replace=T) } llawboot.mean<-apply(llawboot.samp,2,mean) llawboot.med<-apply(llawboot.samp,2,median) llawboot.stddev<-sqrt(apply(llawboot.samp,2,var)) llbmean.se <- rep(0,20) llbmed.se <- rep(0,20) llbsd.se <- rep(0,20) for(i in 50:50:1000) { llbmean.se[i/50] <-sqrt(var(llawboot.mean[1:i])) llbmed.se[i/50] <- sqrt(var(llawboot.med[1:i])) llbsd.se[i/50] <- sqrt(var(llawboot.stddev[1:i])) } llawsamp.samp<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) { llawsamp.samp[,i]<-sample(law82[,2],15,replace=T) } llawsamp.mean<-apply(llawsamp.samp,2,mean) llawsamp.med<-apply(llawsamp.samp,2,median) llawsamp.stddev<-sqrt(apply(llawsamp.samp,2,var)) llsmean.se <- rep(0,20) llsmed.se <- rep(0,20) llssd.se <- rep(0,20) for(i in 50:50:1000) { llsmean.se[i/50] <-sqrt(var(llawsamp.mean[1:i])) llsmed.se[i/50] <- sqrt(var(llawsamp.med[1:i])) llssd.se[i/50] <- sqrt(var(llawsamp.stddev[1:i])) } par(mfrow=c(1,2)) hist(llawboot.mean,prob=T,main="LSAT - Bootstrap - Mean",xlab="Mean",xlim=c(560,640),ylim=c(0,0.04)) hist(llawsamp.mean,prob=T,main="LSAT - Sample - Mean",xlab="Mean",xlim=c(560,640),ylim=c(0,0.04)) hist(llawboot.med,prob=T,main="LSAT - Bootstrap - Median",xlab="Median",xlim=c(540,660),ylim=c(0,0.06)) hist(llawsamp.med,prob=T,main="LSAT - Sample - Median",xlab="Median",xlim=c(540,660),ylim=c(0,0.06)) hist(llawboot.stddev,prob=T,main="LSAT - Bootstrap - Std Deviation",xlab="Std Dev",xlim=c(10,65),ylim=c(0,0.08)) hist(llawsamp.stddev,prob=T,main="LSAT - Sample - Std Deviation",xlab="Std Dev",xlim=c(10,65),ylim=c(0,0.08)) llbmean.bias <- rep(0,20) llbmed.bias <- rep(0,20) llbsd.bias <- rep(0,20) for(i in 50:50:1000) { llbmean.bias[i/50] <- mean(llawboot.mean[1:i])-mean(law[,1]) llbmed.bias[i/50] <- mean(llawboot.med[1:i])-median(law[,1]) llbsd.bias[i/50] <- mean(llawboot.stddev[1:i])-sqrt(var(law[,1])) } llsmean.bias <- rep(0,20) llsmed.bias <- rep(0,20) llssd.bias <- rep(0,20) for(i in 50:50:1000) { llsmean.bias[i/50] <- mean(llawsamp.mean[1:i])-mean(law82[,2]) llsmed.bias[i/50] <- mean(llawsamp.med[1:i])-median(law82[,2]) llssd.bias[i/50] <- mean(llawsamp.stddev[1:i])-sqrt(var(law82[,2])*81/82) } par(mfrow=c(1,2)) hist(llawboot.mean,prob=T,main="LSAT - Bootstrap - Mean",xlab="Mean",xlim=c(560,640),ylim=c(0,0.04)) points(mean(law[,1]),0) hist(llawsamp.mean,prob=T,main="LSAT - Sample - Mean",xlab="Mean",xlim=c(560,640),ylim=c(0,0.04)) points(mean(law82[,2]),0) hist(llawboot.med,prob=T,main="LSAT - Bootstrap - Median",xlab="Median",xlim=c(540,660),ylim=c(0,0.06)) points(median(law[,1]),0) hist(llawsamp.med,prob=T,main="LSAT - Sample - Median",xlab="Median",xlim=c(540,660),ylim=c(0,0.06)) points(median(law82[,2]),0) hist(llawboot.stddev,prob=T,main="LSAT - Bootstrap - Std Deviation",xlab="Std Dev",xlim=c(10,65),ylim=c(0,0.08)) points(sqrt(var(law[,1])),0) hist(llawsamp.stddev,prob=T,main="LSAT - Sample - Std Deviation",xlab="Std Dev",xlim=c(10,65),ylim=c(0,0.08)) points(sqrt(var(law82[,2])*81/82),0) glawboot.samp<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) { glawboot.samp[,i]<-sample(law[,2],15,replace=T) } glawboot.mean<-apply(glawboot.samp,2,mean) glawboot.med<-apply(glawboot.samp,2,median) glawboot.stddev<-sqrt(apply(glawboot.samp,2,var)) glbmean.se <- rep(0,20) glbmed.se <- rep(0,20) glbsd.se <- rep(0,20) for(i in 50:50:1000) { glbmean.se[i/50] <-sqrt(var(glawboot.mean[1:i])) glbmed.se[i/50] <- sqrt(var(glawboot.med[1:i])) glbsd.se[i/50] <- sqrt(var(glawboot.stddev[1:i])) } glawsamp.samp<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) { glawsamp.samp[,i]<-sample(law82[,3],15,replace=T) } glawsamp.mean<-apply(glawsamp.samp,2,mean) glawsamp.med<-apply(glawsamp.samp,2,median) glawsamp.stddev<-sqrt(apply(glawsamp.samp,2,var)) glsmean.se <- rep(0,20) glsmed.se <- rep(0,20) glssd.se <- rep(0,20) for(i in 50:50:1000) { glsmean.se[i/50] <-sqrt(var(glawsamp.mean[1:i])) glsmed.se[i/50] <- sqrt(var(glawsamp.med[1:i])) glssd.se[i/50] <- sqrt(var(glawsamp.stddev[1:i])) } par(mfrow=c(1,2)) hist(glawboot.mean,prob=T,main="GPA - Bootstrap - Mean",xlab="Mean",xlim=c(2.85,3.35),ylim=c(0,8)) hist(glawsamp.mean,prob=T,main="GPA - Sample - Mean",xlab="Mean",xlim=c(2.85,3.35),ylim=c(0,8)) hist(glawboot.med,prob=T,main="GPA - Bootstrap - Median",xlab="Median",xlim=c(2.8,3.45),ylim=c(0,7)) hist(glawsamp.med,prob=T,main="GPA - Sample - Median",xlab="Median",xlim=c(2.8,3.45),ylim=c(0,7)) hist(glawboot.stddev,prob=T,main="GPA - Bootstrap - Std Deviation",xlab="Std Dev",xlim=c(0.08,0.32),ylim=c(0,14)) hist(glawsamp.stddev,prob=T,main="GPA - Sample - Std Deviation",xlab="Std Dev",xlim=c(0.08,0.32),ylim=c(0,14)) glbmean.bias <- rep(0,20) glbmed.bias <- rep(0,20) glbsd.bias <- rep(0,20) for(i in 50:50:1000) { glbmean.bias[i/50] <- mean(glawboot.mean[1:i])-mean(law[,2]) glbmed.bias[i/50] <- mean(glawboot.med[1:i])-median(law[,2]) glbsd.bias[i/50] <- mean(glawboot.stddev[1:i])-sqrt(var(law[,2])) } glsmean.bias <- rep(0,20) glsmed.bias <- rep(0,20) glssd.bias <- rep(0,20) for(i in 50:50:1000) { glsmean.bias[i/50] <- mean(glawsamp.mean[1:i])-mean(law82[,3]) glsmed.bias[i/50] <- mean(glawsamp.med[1:i])-median(law82[,3]) glssd.bias[i/50] <- mean(glawsamp.stddev[1:i])-sqrt(var(law82[,3])*81/82) } par(mfrow=c(1,2)) hist(glawboot.mean,prob=T,main="GPA - Bootstrap - Mean",xlab="Mean",xlim=c(2.85,3.35),ylim=c(0,8)) points(mean(law[,2]),0) hist(glawsamp.mean,prob=T,main="GPA - Sample - Mean",xlab="Mean",xlim=c(2.85,3.35),ylim=c(0,8)) points(mean(law82[,3]),0) hist(glawboot.med,prob=T,main="GPA - Bootstrap - Median",xlab="Median",xlim=c(2.8,3.45),ylim=c(0,7)) points(median(law[,2]),0) hist(glawsamp.med,prob=T,main="GPA - Sample - Median",xlab="Median",xlim=c(2.8,3.45),ylim=c(0,7)) points(median(law82[,3]),0) hist(glawboot.stddev,prob=T,main="GPA - Bootstrap - Std Deviation",xlab="Std Dev",xlim=c(0.08,0.32),ylim=c(0,14)) points(sqrt(var(law[,2])),0) hist(glawsamp.stddev,prob=T,main="GPA - Sample - Std Deviation",xlab="Std Dev",xlim=c(0.08,0.32),ylim=c(0,14)) points(sqrt(var(law82[,3])*81/82),0) lawbootr.index<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) lawbootr.index[,i] <- sample(1:15,15,replace=T) lawbootr.samp<-array(0,c(15,2,1000)) for (i in 1:1000) { lawbootr.samp[,,i] <- as.matrix(law[lawbootr.index[,i],]) } lawbootr.corr <- rep(0,1000) for (i in 1:1000) { lawbootr.corr[i] <- cor(lawbootr.samp[,1,i],lawbootr.samp[,2,i]) } lbr.se <- rep(0,20) for (i in 50:50:1000) lbr.se[i/50] <- sqrt(var(lawbootr.corr[1:i])) lbr.bias <- rep(0,20) for (i in 50:50:1000) lbr.bias[i/50] <- mean(lawbootr.corr[1:i]) - cor(law[,1],law[,2]) lawsampr.index<-matrix(0,ncol=1000,nrow=15) for (i in 1:1000) lawsampr.index[,i] <- sample(1:82,15,replace=F) lawsampr.samp<-array(0,c(15,2,1000)) for (i in 1:1000) { lawsampr.samp[,,i] <- as.matrix(law82[lawsampr.index[,i],2:3]) } lawsampr.corr <- rep(0,1000) for (i in 1:1000) { lawsampr.corr[i] <- cor(lawsampr.samp[,1,i],lawsampr.samp[,2,i]) } lsr.se <- rep(0,20) for (i in 50:50:1000) lsr.se[i/50] <- sqrt(var(lawsampr.corr[1:i])) lsr.bias <- rep(0,20) for (i in 50:50:1000) lsr.bias[i/50] <- mean(lawsampr.corr[1:i]) - cor(law82[,2],law82[,3]) par(mfrow=c(1,2)) hist(lawbootr.corr,prob=T,br=(-2:20)/20,main="Bootstrap - Correlation",xlab="Corr",xlim=c(-0.1,1),ylim=c(0,3.5)) hist(lawsampr.corr,prob=T,br=(-2:20)/20,main="Sample - Correlation",xlab="Corr",xlim=c(-0.1,1),ylim=c(0,3.5)) par(mfrow=c(1,2)) hist(lawbootr.corr,prob=T,br=(-2:20)/20,main="Bootstrap - Correlation",xlab="Corr",xlim=c(-0.1,1),ylim=c(0,3.5)) points(cor(law[,1],law[,2]),0) hist(lawsampr.corr,prob=T,br=(-2:20)/20,main="Sample - Correlation",xlab="Corr",xlim=c(-0.1,1),ylim=c(0,3.5)) points(cor(law82[,2],law82[,3]),0) par(mfrow=c(1,2)) hist(law82[,2],main="LSAT",xlab="LSAT") points(law[,1],rep(0,15)) hist(law82[,3],main="GPA",xlab="GPA") points(law[,2],rep(0,15)) par(mfrow=c(1,1)) plot(law82[,2],law82[,3],xlab="LSAT",ylab="GPA",col=gray(0.7)) points(law[,1],law[,2]) legend(650,2.7,c("Sampled","Unsampled"),col=gray(c(0,0.7)),pch=19)