4 Harris interactive conducted a survey in which they asked

4. Harris interactive conducted a survey in which they asked adult Americans (18 years or older) whether they used social media (Facebook , twitter, and so on) regularly. The following table is based on the results of the survey. a. If an adult American is randomly selected, what is the probability that he or she does not use social media? Let E = she does not uses social media hence find P (E)

Solution

a)
p(E) = n( does n\'t uses social media) / n(total) = 192/530 = 0.3622

b)
P(E) = n( He or She is 55+ Years old) /n(total) = 115/530 = 0.2169

P(F) = n(uses social media) / n(total) = 338/530 = 0.6377

P( E n F ) = n( 55+ and uses social media) / n(total) = 49/530 = 0.09245

P( E or F) = p(E) + P(F) - P(E n F) = 0.2169+  0.6377 - 0.09245 = 0.76215