Datasets apartments and apartments_test are artificial,
generated form the same model.
Structure of the dataset is copied from real dataset from PBImisc package,
but they were generated in a way to mimic effect of Anscombe quartet for complex black box models.
data(apartments)a data frame with 1000 rows and 6 columns
m2.price - price per square meter
surface - apartment area in square meters
n.rooms - number of rooms (correlated with surface)
district - district in which apartment is located, factor with 10 levels
floor - floor
construction.date - construction year