# ?aggregate the mean of two variables by month
aggregate(cbind(Ozone, Temp) ~ Month, data = airquality, mean)

# grouped binomial data:
glm(cbind(events, nonevents) ~ x, family = binomial)

# pls::plsr, 
pls(sensory ~ chemical, data = oliveoil)
# sensory and chemical are 2D arrays in the oliveoil data frame