80. Telephone Service The percent P of households in the United States with wireless-only telephone
service from 2005 through 2014 can be approximated
by the model
P = -3.42 + 1.297t In t, 5 st s 14
where t represents the year, with t = 5 corresponding to
2005. (Source: National Center for Health Statistics)
(a) Approximate the percents of households with
wireless-only telephone service in 2008 and 2012.
A (b) Use a graphing utility to graph the function.
(c) Can the model be used to predict the percent of
households with wireless-only telephone service in
2020? in 2030? Explain.