A Pew Research (2009) survey of nationally representative 242 cell phone users, ages 16 to 17 years, found that 52% had talked on the phone while driving.
a. Use these data to estimate, with 95% confidence, the proportion of all 16- to 17-year-old cell phone users who talk on the phone while driving.
b. Do these data provide evidence that a majority of 16- to 17-year-old cell phone users talk on the phone while driving? Explain your reasoning.
c. Without performing any extensive calculations, find the 95% confidence interval for the proportion of all 16- to 17-year-old cell phone users who do not talk on the phone while driving.
d. Suppose that you are planning to conduct a survey in your city to estimate, with 95% confidence, the proportion of 16- to 17-year-old cell phone users who talk on the phone while driving and want the margin to be no bigger than 0.05. What should your sample size be?