Problem 19

  1. experiment

  2. Athletes with injuries on a team

  3. type of program for recovery

  4. 2 different treatments

  5. how long it took for athletes to return to playing

  6. randomized

  7. Not blind

  8. See which program is more effective at healing injuries faster

Problem 31

  1. randomization is important so the results are unbiased. if they could choose, or if the process was in some other way not random, the results might be affected by other factors than the treatment

  2. We could see if doing any exeresize program at all is even helpful

  3. doctors who approved the atheltes to return could not know what treatment was used

  4. No, since the standard deviation is so high.

Problem 33

  1. differences were greater than sampling variation

  2. testtakers were either given music by Glass, Mozart, or noone before the test

  3. Not really. little improvement by mozart group

  4. No, mozart doesnt seem to change much in terms of test scores.

Problem 37

  1. use random numbers to determine which should be filled (00-49 filled, 50-99 not)

  2. Slightly above avaerage but not significant

  3. somewhere that is out of the sampling variation, say 70% or more. ## Problem 41

  4. differnce is higher than sampling variation

  5. Observation study

  6. No, since this is not nessecasily causation. People generally do more dangeous stuff on the weekend. additionally, waiting to go into the hospital might futher worsen your condition

  7. Riskier actions on weekends. more dirnking and drugs and the like

Problem 47

  1. Parachute or not

  2. Forcefully and randomly chosing citizens

  3. a fake parachute

  4. a real parachute

  5. wether the participants lived

  6. wether and location

  7. randomly and blindly assign parachutes

  8. have the people giving the parachutes not know wether they are real or not.