# dati
library(carData)
data(SLID)

# INDICIZZAZIONE

str(SLID[1])
str(SLID[1:10,])

# table(SLID["language"])
# table(SLID[,"language"])
table(SLID$language)  

table(SLID[SLID$age<66,"language"])

table(SLID[SLID$age<66 & SLID$language!="Other", c(5,4)])


# ARGOMENTO SUBSET

t.test(wages~sex, alternative='two.sided',
       conf.level=.95, data=SLID, subset = SLID$age<66)


# FUNZIONE SUBSET

# subset con tutte le variabili
newdata <- subset(SLID, language == "English")

# subset con alcune variabili (ID e Weight)
newdata <- subset(SLID, age > 24 | age < 65, 
                  select=c(ID, Weight))