meta-features store vector of numbers instead of aggregates

[janvanrijn]

Currently we store (for numeric columns):

• Mean X of numeric atts
• Stdev of X of numeric atts
• Quartile {1, 2, 3} of X of numeric atts
• Min of X of numeric atts
• Max of X of numeric atts

Where X = {mean, stdev, kurtosis, skewness}. Something similar for information theoretic measures of nominal atts.

This selection is arbitrary and not well supported in the literature.

Much better would be to store a vector of each value per attribute, giving the possibility to researchers to calculate these values client-side.