72 24) 20/39 28 25) S = {hhh, hht, hth, thh, tth, tht, htt, ttt} 10% a. P(tails exactly twice) = 3/8 b. P(heads at least once) = 7/8 12.5% 8.26% 26) 3.75% 720 P(placebo and improvement) = 46% 3/14 1/6, ½, 1/3 7/29 1/169, 1/52 12 60 13) S = {hhhh, httt, thtt, ttht, ttth, thth, htht, tthh, hhtt, thht, htth, thhh, hthh, hhth, hhht, tttt} 3276 34) 1/6, 11/18 P(exactly one head) = ¼ 5/12 5/104 ¼ b) ½ c) ¼ d)3/4 e)1/4 14/55 $3.25 1/55 1/18 4/55 78 3/110 6227020800 (It is fine to simply write 13!) 20) 10 $5 64.3% $0 (breaks even) Dependent: outcome is based on previous event Independent: outcome is not based on previous event