need help with question. I don't know where to start.

Much Internet advertising is priced based on click-through activity. A prospect is shown an ad on a host website based on search words he or she might have entered in a search engine such as Google or Bing. If the prospect clicks directly on the ad they see on the host website to visit the advertiser’s site, the ad is considered effective and advertiser must pay the host website for the ad. But research reveals that while all prospects do not click on the ad they are shown on a host website, many do visit the advertiser’s site. They simply key in the advertiser’s URL directly into their browser or search engine. How would you design an experiment to determine if non-click-through ads displayed on your host website were actually effective in getting a prospect to an advertiser’s website?