STAT 124 Lecture Notes - Lecture 2: Mutual Exclusivity, Sample Space, Probability Theory

• School: UBC Okanagan, UBC OK
• Department: Statistics
• Course: STAT 124
• Professor: Gill Paramjit

Document Summary

It can be helpful to model a process aa random even if it is not truly random (cid:862)(cid:396)a(cid:374)do(cid:373)(cid:863) is (cid:374)ot a s(cid:455)(cid:374)o(cid:374)(cid:455)(cid:373) of (cid:862)haphaza(cid:396)d(cid:863) (cid:271)ut a des(cid:272)(cid:396)iptio(cid:374) of a kind of order that emerges only in the long run. Addition rule for disjoint events: the probability that a or b is then the sum of their individual probabilities, p(a or b) = p(a) + p(b, example: If you flip 2 coins, there are four possible disjoint outcomes: The probability of each of these events is 0. 25. The p(cid:396)o(cid:271)a(cid:271)ilit(cid:455) that (cid:455)ou o(cid:271)tai(cid:374) (cid:862)o(cid:374)l(cid:455) heads o(cid:396) o(cid:374)l(cid:455) tails(cid:863) is: P(hh or tt) = p(hh) + p(tt) = 0. 25 + 0. 25 = 0. 50. Note: (cid:449)he(cid:374) (cid:449)e (cid:449)(cid:396)ite (cid:862)o(cid:396)(cid:863) (cid:449)e (cid:373)ea(cid:374) (cid:862)a(cid:374)d/o(cid:396)(cid:863) u(cid:374)less e(cid:454)pli(cid:272)itl(cid:455) stated othe(cid:396)(cid:449)ise: thus, a or b occurs means a, b, or both a and b occur means a, b, or both a and b occur.