Drug tests Major League Baseball tests players to see whether they are using performance-enhancing drugs. Officials select a team at random, and a drug-testing crew shows up unannounced to test all 40 players on the team. Each testing day can be considered a study of drug use in Major League Baseball. a) What kind of sample is this? b) Is that choice appropriate?
Econ 225: Ex. You have 12 shirts in your closet. 9 White shirts, 3 Black shirts. Suppose you pick a shirt at random. Put it on, when you get home you take it off and wash it. Suppose you do the same thing the next day, without replacing the first shirt. What is the probability that both shirts you picked out are white Day 1: P(Picking a white shirt)= 9/12 (9 white shirts/ 12 total shirts) Day 2: P(Picking white shirt) = 8/11 (8 White shirts/ 11 total shirts; given that you picked a white shirt on the first day) (Probability of day 1) * (Probability of day 2; Given that day 1’s shirt was white) = (9/12) * (8/11) = .55 Whatever happens on the first day will affect what happens on the second day. It is a dependent probability because day 2 depe