A group of students consisting of 20 males and 20 females were selected to participate in a research study.  If a random sample of n =4 students is selected and the first three are all females, what is the probability that the fourth student selected will be a male?

Suppose 33.3% of high school students eat pizza and 42% drink soda. If 17.3% of high school students eat pizza and drink soda, what is the probability that a randomly chosen high student will either eat pizza, drink soda, or both?

WINDO In a survey of consumers aged 12 and older, respondents were asked how many cell phones were in use by the household. (No two respondents were from the same household.) Among the respondents, 208 answered "none," 285 said "one," 361 said "two," 140 said "three," and 56 responded with four or more. A survey respondent is selected at random. Find the probability that his/her household has four or more cell phones in use. Is it unlikely for a household to have four or more cell phones in use? Consider an event to be unlikely if its probability is less than or equal to 0.05. P(four or more cell phones) = (Round to three decimal places as needed.) M

Airlines report that 45% of its flights are on time.  In a random sample of 80 flights, what is the probability that exactly 42 will be on time?