Talk about it. Business and Consumer Law. Ask an attorney to help you understand. Get help here. And sometimes the only difference between the two is the color of the background.
Big businesses can afford to spend a lot of money testing ads.
Small businesses on limited budgets can't. The answer is to test your ads for free - on your own web site. If your budget is small keep the test simple. Try changing the background color of the ad, or the text in the banner. Run the ad on your own site to see if there are any differences.