STAT 1053 Lecture Notes - Lecture 8: Mutual Exclusivity
Document Summary
The standard example of a binomial rv is the number of heads in n tosses of a coin. The tosses are independent, and the probability of head is the same for each toss. We worked through an example with n=3 tosses and calculated the probabilities. = p(hht) + p(hth) + p(thh) (mutually exclusive events) The probability that x takes a particular value has two parts--the probability of a particular outcome or sequence that has the appropriate number of h"s and t"s, and that is multiplied by the number of such sequences. P(x=2) =(number of outcomes in which x=2) x (. 6)number of h x (. 4)number of t . Of course, any outcome corresponding to the event x=2 in three tosses, must have, number of h = 2 & number of t = 3 -2 =1 (number of tosses number of h). The more abstract notation at the top is helpful in thinking about the general case, which we"ll consider next.
