Transforming variables

To group the variable Date into a new variable Period:

> Period <- Date
> Period[(Date>650)&(Date<=1200)] <- 1
> Period[(Date>100)&(Date<=650)] <- 2
> Period[(Date<=100)] <- 3
> table(Period)
Period
 1  2  3 
20 18  2 

> barplot(table(Period))

> barplot(table(Mat,Period), beside=TRUE)

To create the new variable "maximum length / maximum width ratio", Lewirat:

> Lewirat <- Maxle/Maxwi

To create the new variable "socket length as percentage of maximum length", Socperc:

> Socperc <- (Socle/Maxle)*100