... ways to assign the first element, for 94 CHAPTER 3. COMBINATORICSn = 0 110 1 10 45 120 21 0 25 2 21 0 120 45 10 1 9 1 9 36 84 126 126 84 36 9 1 8 1 8 28 56 70 56 28 8 17 1 7 21 35 35 21 7 ... {a1,a 2 ,a3,a4} can be written in theformσ = 123 4 21 43,indicating that a1went to a 2 , a 2 to a1, a3 to a4, and a4 to a3.Ifwealwayschoosethetoprowtobe 123 4then, to prescribe ... Binomial distributions. 78 CHAPTER 3. COMBINATORICSNumber of people Probability that all birthdays are different 20 .5885616 21 .5563117 22 . 524 3047 23 .4 927 028 24 .4616557 25 .4313003Table 3.1:...