cursor skips around when i type on my MacBook Air

In Pages or Textedit, when I type, the cursor often skips ahead or back or up or down a line or two. i rest my fingers on the keys, and it DOES NOT SKIP, only when I'm typing. I'm not hitting the shift key, just typing...and the next thing I know it's skipped up 3 lines, or back 4 words, etc. It's most annoying, and I can't seem to figure out why the cursor keeps jumping around so.

What's happening, and how do I fix it.

Is there something I should adjust?

Thanks,

Hal