Webcredible, a UK-based consulting firm specializing in websites, intranets, mobile devices, and applications, conducted a survey of 1,132 mobile phone users between February and April 2009. The survey found that 52% of mobile phone users are now using the mobile Internet. (Data extracted from "Email and Social Networking Most Popular Mobile Internet Activities," www.webcredible.co.uk, May 13, 2009.) The authors of the article imply that the survey proves that more than half of all mobile phone users are now using the mobile Internet.
a. Use the five-step p-value approach to hypothesis testing and a 0.05 level of significance to try to prove that more than half of all mobile phone users are now using the mobile Internet.
b. Based on your result in (a), is the claim implied by the authors valid?
c. Suppose the survey found that 53% of mobile phone users are now using the mobile Internet. Repeat parts (a) and (b).
d. Compare the results of (b) and (c).