Linear regression

Example

 allergy_data<-read.csv('https://raw.githubusercontent.com/kunal0895/RDatasets/master/allergy_data.csv')
 library(rpart.plot)
 library(rpart)
 separate_line <- 0.9*nrow(allergy_data)
 validation.testing <- allergy_data[(separate_line+1):nrow(allergy_data),]
 validation.training <- allergy_data[1:separate_line,]
 train.tree.v <- rpart(POLLEN~ TEMP + HUMIDITY, data=validation.training)
 pred.tree.v <- predict(train.tree.v,newdata=validation.testing)
 mean((pred.tree.v - validation.testing$POLLEN)^2)
 train.lm.v <- lm(POLLEN~ TEMP + HUMIDITY, data=validation.training)
 pred.lm.v <- predict(train.lm.v,newdata=validation.testing)
 mean((pred.lm.v - validation.testing$POLLEN)^2)