frequency of positive and negative numbers, sizes of numbers and frequency of alteration of polarity

How to calculate frequency of positive and negative numbers and define and
calculate frequency of alteration of polarity?

Surely, we can use frequency of alteration of polarity and level of change
(e.g., size of positive and negative numbers) to measure degree and
frequency of alteration.

Any ideas in doing so in postgres tables' columns full of positive and
negative numbers?

Regards,

David