What Proportion of Adults and Teens Text Message? A study of n = 2252 adults age 18 or older found that 72 % of the cell phone users send and receive text messages.' A study of n = 800 teens age 12 to 17 found that 87 % of the teen cell phone users send and receive text messages. What is the best estimate for the difference in the proportion of cell phone users who use text messages, between adults (defined as 18 and over) and teens? 1Lenhart, A."Cell Phones and American Adults," Pew Research Center's Internet and American Life Project, accessed at http://pewinternet.org/Reports/2010/Cell-Phones-and-American-Adults/Overview.aspx. (a) Give the notation (as a difference with a minus sign) for the quantity we are trying to estimate. Let group'l be the adult cell phone users and let group 2 be the teen cell phone users. : P1 :: P2 :: p : '2 : P1 : P2 The notation is SEP