Question

example 3
try it! apply the conditional probability formula

1. what is the

probability that a
surveyed student
plans to attend but
is not a fan of the
group?
concert survey results
students who plan to attend concert

• 70% of students plan to attend,
• 80% of students who plan to attend

are fans of the band.
students who do not plan to attend

• 30% of students do not plan to attend,
• 25% are fans of the band.

example 4
try it! use conditional probability to make a decision

1. the marketer also has data from desktop computers. which product is most

likely to be purchased after a related search?
computer search and buying behavior
(% of computer - based site visitors)

Explanation:

Step1: Calculate the probability for each product

For product \(Q\):
The probability \(P(Q)=\frac{10\%}{35\%}=\frac{10}{35}=\frac{2}{7}\approx0.286\)
For product \(R\):
The probability \(P(R)=\frac{9\%}{28\%}=\frac{9}{28}\approx0.321\)
For product \(L\):
The probability \(P(L)=\frac{8\%}{26\%}=\frac{8}{26}=\frac{4}{13}\approx0.308\)
For product \(M\):
The probability \(P(M)=\frac{5\%}{24\%}=\frac{5}{24}\approx0.208\)

Answer:

Product \(R\) is most likely to be purchased after a related search.