A study of n = 2252 adults age 18 or older found that 72% of the cell phone users send and receive text messages.1 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 (dened as 18 and over) and teens?

Give the value of the best estimate.

Enter the exact answer.