An online company is hoping to sell a new product by placing a pop-up advertisement on their website. There are two different designs for the advertisement, and the company would like to determine which one is more effective, as measured by clicks and purchases. For the first 200 visitors to the updated website, half were randomly assigned to receive advertisement 1 and half to receive advertisement 2. The two-way table summarizes the results: Customer Behavior Did not click Clicked, no purchase Clicked, made purchase Total Advertisement 1 70 8 22 100 Advertisement 2 64 20 16 100 Total 134 28 38 200 (a) Is this study an observational study or an experiment

This is a case of experiment, as the visitors are assigned randomly to one of the two advertisements. The researcher intervene introducing a variable (the type of advertisement) and then study the results.

If it was an observational study, the researcher would observe, for example, the behaviour of the visitor without defining or controlling the exposure to one of the advertisement for a group of visitors.