How is the macintosh operating system safer than a windows operating system?

Because there are not as many OS X (or even Linux) users than Windows, virus programmers target the more widely used Windows where they can do more damage. It doesn't mean that Macs are safer though. It's just that bad people don't give much attention to them. It's still not worth their time. Perhaps when you see a significant rise in OS X usage, you will start hearing about a lot of virus designed for OS X.