[teruakohatu]

> seeing if there were any "attributes" that they could not easily explain

I am sure there are many, but the more obscure the less they probably contribute to class probability.

Sitting down is probably an indicator of old age because 90 year olds are sitting for more hours than a 20 year old. It probably does not contribute a lot but may contribute something.

More obscure might be a color of shirt that is more popular with 90 year old men in the USA than men under 50.