from walpole 5.61
Suppose the probability is 0.8 that any given person wll believe a tale about the transgressions of a famous actress.
a) the sixth person to hear this tale is the forth one to believe it ?
b) what is the probability that the thrd person to hear this tale is the first one to believe it ?
i know p= 0.80 and q = 1- 0.8=0.20
but how should i apply the above to the questions ?
i don't even know how many people are listening to the tale.
pls explain.
Hello, Hazel!
Let = the person believes the rumor.Suppose the probability is 0.8 that any given person will believe a rumor of a scandal.
a) What is the probability that the 6th person to hear the rumor is the 4th one to believe it ?
and = the person does not believe the rumor.
Among the first 5 who heard the rumor, there were 3 B's (and 2 N's).
. . This probability is: .
Then the 6th person is a B: .
Therefore: .
b) What is the probability that the 3rd person to hear this rumor is the first to believe it ?
The first two were N's: .
The third is a B: .
Therefore: .