Podcast downloading
The Podcast Alley Web site recently reported that they have 91,701 podcasts available for downloading, with 6,070,164 episodes.20 The Pew Research Center performed two surveys about podcast downloading. The first was conducted between February and April 2006 and surveyed 2822 Internet users. It found that 198 of these said that they had downloaded a podcast to listen to it or view it later at least once. In a more recent survey, conducted in May 2008, there were 1553 Internet users. Of this total, 295 said that they had downloaded a podcast to listen to it or view it later
(a) Refer to the table that appears at the beginning of this section (page 344). Fill in the numerical values of all quantities that are known.
(b) Find the estimate of the difference between the proportion of Internet users who had downloaded podcasts as of February to April 2006 and the proportion as of May 2008.
(c) Is the large-sample confidence interval for the difference in two proportions appropriate to use in this setting? Explain your answer.
(d) Find the 95% confidence interval for the difference.
(e) Convert your estimated difference and confidence interval to percents.
(f) One of the surveys was conducted between February and April, whereas the other was conducted in May. Do you think that this difference should have any effect on the interpretation of the results? Be sure to explain your answer.