In which of the following situations is the probability calculated empirically?
[] A new drug was successful in treating 90 out of 100 test subjects, so it is estimated that the drug will have a 90% success rate when prescribed to patients.
[] In a poll by a major news network, 200 out of 400 people said that they approved of Congress, so it is estimated that the approval rate for Congress is 50%.
[] Out of 1000 fans at a rock concert, 600 are male, so if a random person gets called to the stage, the probability that that person will be male is 60%.
[] A doctor believes that there is a 90% chance his patient will survive a procedure.
[] In a city with 50,000 people, 5000 are unemployed, so the probability of a random person in this city being unemployed is 10%.