3.4 Contingency tables

$\text{P(person is a car phone user) =}$

$\text{P(person had no violation in the last year) =}$

$\text{P(person had no violation in the last year AND was a car phone user) =}$

$\text{P(person is a car phone user OR person had no violation in the last year) =}$

$\text{P(person is a car phone user GIVEN person had a violation in the last year) =}$

$\text{P(person had no violation last year GIVEN person was not a car phone user) =}$

Complete the table.

Are the events "being female" and "preferring the coastline" independent events?

Let $F$ = being female and let $C$ = preferring the coastline.

• a $\text{P(F AND C)}$ =
• b $\mathrm{P(F)}\cdot \mathrm{P(C)}$ =

Are these two numbers the same? If they are, then $F$ and $C$ are independent. If they are not, then $F$ and $C$ are not independent.

Find the probability that a person is male given that the person prefers hiking near lakes and streams. Let $\text{M}$ = being male and let $\text{L}$ = prefers hiking near lakes and streams.

• a What word tells you this is a conditional?
• b Fill in the blanks and calculate the probability: $\text{P(\_\_\_|\_\_\_)}=\mathrm{\_\_\_}$ .
• c Is the sample space for this problem all 100 hikers? If not, what is it?

Find the probability that a person is female or prefers hiking on mountain peaks. Let $F$ = being female and let $P$ = prefers mountain peaks.

• a $\text{P(F)}=$
• b $\text{P(P)}=$
• c $\text{P(F AND P)}=$
• d Therefore, $\text{P(F OR P)}=$

Complete the probability contingency table. Calculate the entries for the totals. Verify that the lower-right corner entry is 1.

What is the probability that Alissa does not catch Muddy?

What is the probability that Muddy chooses Door One OR Door Two given that Muddy is caught by Alissa?