SplitScreen is a marketing research company that tests television advertisements. SplitScreen has an agreement with a cable television company in a medium-sized city in Iowa. The cable company can send up to four different television ads simultaneously to different households. SplitScreen also has agreements with the three largest grocery store chains, which will provide scanner data to SplitScreen. About 25 percent of the residents have SplitScreen scan cards that are scanned when items are bought at the grocery store and which allows SplitScreen to identify who bought what grocery products. For allowing SplitScreen access to their television hook-ups and their grocery purchases information, residents receive bonus points that can be used to buy products in a special points catalog. Identify and diagram the true experimental designs possible using the SplitScreen system. Assess the internal and external validity of SplitScreen’s system.