New features can be created by performing mathematical and statistical operations over existing variables. We previously mentioned that we can calculate the total debt by summing up the debt across individual financial products:
Total debt = car loan debt + credit card debt + mortgage debt
We can also derive other insightful features using alternative statistical operations. For example, we can determine the maximum debt of a customer across financial products, the minimum time they spent surfing one page of our website, or the mean time they spent reading an article of our magazine:
maximum debt = max(car loan balance, credit card balance, mortgage balance)
minimum time on page = min(time on homepage, time on about page, time on the contact us page)
mean time reading article = (time on article 1 + time on article 2...
