air.df_data.frame(air)

print(air.df)

pairs(air.df)

air.lm_lm(ozone~temperature+wind+radiation, data=air)

summary(air.lm)

par(mfrow=c(2,3))

plot(air.lm, ask=F)

drop1(air.lm)

ozone0.lm_lm(ozone~1,data=air)
ozone0.add1_add1(ozone0.lm,~temperature+wind+radiation)
print(ozone0.add1)