An employee who has just been put in charge of the pet adoption fundraiser thinks that a personal phone call to recent adopters asking for a donation will bring in more monetary contributions, on average, than sending recent adopters a personal mailing asking for a donation. she plans to randomly select 25 recent adopters to reach out for donations with a personal phone call and will randomly select another 25 recent adopters to send a personal note with a donation request. she will record and compare the donation amounts (in dollars).

When cell phones were first entering the market, they were relatively large and reception was undependable. all cell phones were essentially the same. but as the technology developed, many competitors entered, introducing features unique to their phones. today, cell phones are only a small fraction of the size and weight of their predecessors. consumers can buy cell phones with color screens, cameras, internet access, daily planners, or voice activation (and any combination of these features). the history of the cell phone demonstrates what marketing trend?