27. Social Media Use. A marketing firm would like to test-market the name of a new energy drink targeted at 18- to 29-year-olds via social media. A study by the Pew Research Center found that 35% of U.S. adults (18 and older) do not use social media (Pew Research Center website, October 2015). The percentage of U.S. young adults age 30 and older is 78%. Suppose that the percentage of the U.S. adult population that is either age 18-29 or uses social media is 67.2%. a. What is the probability that a randomly selected U.S. adult uses social media? b. What is the probability that a randomly selected U.S. adult is aged 18-29? c. What is the probability that a randomly selected U.S. adult is 18-29 and a user of social media? 19. Impact of Global Warming. Do you think global warming will have an impact on you during your lifetime? A 2014 CBS News/New York Times poll of 1000 adults in the United States asked this question (CBS News website). Consider the responses by age groups shown below. Response Age 18-29 30+ Yes 134 293 No 131 432 2 8 Unsure a. What is the probability that a respondent 18-29 years of age thinks that global warming will not pose a serious threat during his/her lifetime? b. What is the probability that a respondent 30+ years of age thinks that global warming will not pose a serious threat during his/her lifetime? c. For a randomly selected respondent, what is the probability that a respondent answers yes? d. Based on the survey results, does there appear to be a difference between ages 18-29 and 30+ regarding concern over global warming?