Conditional Probability and Independence

When renting two cars, you decide to choose one of the blue cars. Your friend then chooses one of the red cars. Are these independent events?

• Yes

• No

You choose to rent two cars. You choose the only blue car. Your friend chooses a red car. These are independent events.

• True

• False

The probability that you will get lung cancer if you smoke is the same as the probability of you being a smoker if you have lung cancer.

• True

• False

A bag of 30 marbles has 9 black, 7 white, 6 yellow and the rest are green. What is the probability, in a percentage, that you will draw out a white or a yellow?

• 20%

• 35%

• 43%

• 57%

You draw two cards out of a deck of cards. As a decimal, what is the probability that you draw an Ace or a 7?

• 0.15

• 0.20

• 0.50

• 0.65

Using the Venn Diagram, how many people like to ski or ride snowmobiles?

• 15

• 45

• 69

• 89

In your English class of 32 students, 7 of them play soccer and 10 run cross country. Of those same students, four play both soccer and run cross country. Find the probability that one of the students, chosen at random, plays soccer or runs cross country.

• 12.5%

• 40.6%

• 53.1%

• 65.6%

Events A and B are NOT mutually exclusive. P(A) = 0.3, P(B) = 0.45 and P(A n B) is 0.12. Find P(A U B).

• 0.18

• 0.33

• 0.63

• 0.75

In Colorado, the probability that a person owns skis is 65% and the probability that they own skis and a snowboard is 25%. Find the probability that a person owns a snowboard given that they already own skis.

• 25%

• 38%

• 65%

• 78%

These days, 96.7% of Americans own a TV and 25.4% of Americans own a TV and a laptop. Find the probability that an American owns a laptop given that they own a TV.

• 96.7%

• 81.2%

• 71.3%

• 26.2%