a The two-way table should show households subscribing and not subscribing to the two different newspapers.
B
b Find the sum of P(Both), P(Only Weekly), and P(Only Daily).
C
c Divide the percentage of daily subscribers with the percentage of subscribers.
A
aDiagram:
B
b 77 %
C
c 84 %
Practice makes perfect
a The two-way table should show households subscribing and not subscribing to the two different newspapers.
b The people that subscribe to at least one paper is the sum of the percentages of the people subscribing to both papers, the subscribers of only the daily paper, and the subscribers of only the weekly paper.
P(Both)+P(Only Weekly)+P(Only Daily)
Let's highlight these areas of the diagram from Part A.
From the exercise we know that 25 % of the households subscribe to both papers, 65 % subscribe to the weekly paper, and 37 % subscribe to the daily paper. With this information, we can calculate the percentages of households who only subscribed to the daily paper and weekly local.
Only Daily: 65 % -25 %=40 %
Only Weekly: 37 % -25 %=12 %
Let's add this information to the diagram.
By adding these percentages we can determine the probability of a household subscribing to at least one paper.
25 % +12 %+40 % = 77 %
c From Part B we know that 77 % of the households subscribe to at least one paper. Of these households, 65 % subscribe to the daily paper. With this information we have enough to calculate the probability of Charlie receiving the daily paper given that he is a subscriber.
