The probability of event A occurring is P(A) = n(A)/n(S) where n(A) = number of ways that outcome A can occur and n(S) = total number of possible outcomes.
1) The number of females under 25 is 118, so n(A) = 118. There are 1219 total people, so n(S) = 1219. Hence the probability of picking one of the 118 females under 25 from among all 1219 people is P(F,<25) = 118/1219 = ___?
2) Here we want a female or someone between 25 and 45. There are 585 females and 448 people between 25 and 45. So you might think n(A) = 585 + 448. But if you look at the two way table, you'll see that the 152 females between 25 and 45 are counted twice, once in each total. We should only count them once, so we need to subtract 152 to eliminate the double count. So n(A) = 585 + 448 - 152. n(S) is still 1219. So P(F or 25-45) = (585+448-152)/1219 = ____?
