EXAMPL 1

mydata <- data.frame("ID"=c(1, 2, 3, 4, 5),
                     "Height"=c(100, 200, 240,300, 350),
                     "weight"=c(30,34,32,34,22))

mean(mydata$Height)

## [1] 238

summary(mydata[,-1])

##      Height        weight    
##  Min.   :100   Min.   :22.0  
##  1st Qu.:200   1st Qu.:30.0  
##  Median :240   Median :32.0  
##  Mean   :238   Mean   :30.4  
##  3rd Qu.:300   3rd Qu.:34.0  
##  Max.   :350   Max.   :34.0

mydata$gender <- c("F","M","M","M","M")

mydata$BMI <-  round(mydata$weight/(mydata$Height/100)*2,)