How do you compare negative numbers with positive numbers?

[Charles Szasz]

I am computing an average of a series of numbers and then comparing each number with the average, which yields a deviation. Of course, there are instances where a negative deviation will occur when it is below the average. 

Here is my problem. I need to be able to compare a negative number with a positive number and then give the user feedback about whether the negative number is greater in magnitude than the positive number. For example, comparing -3.5 with 2.23. How do you do this?

Charles Szasz
cszasz at mac.com