Probability Practice

You read in a book on poker that the probability of being dealt three of a kind in a five-card poker hand is 1/50. What does this mean?

• If you dealt thousands of poker hands, the fraction of them that contain three of a kind will be very close to 1/50.
• If you deal 50 poker hands, then one of them will contain  three of a kind.
• If you deal 10,000 poker hands, then 200 of them will contain three of a kind.
• A probability of 0.02 is somebody's best guess for a probability of being dealt three of a kind.

People with type O-negative blood are universal donors. That is, any patient can receive a transfusion of O-negative blood. Only 7.2% of the American population has O-negative blood. If 10 people appear at random to give blood, what is the probability that at least 1 of them is a universal donor?

• 0.526
• 0.72
• 0.28
• 0

According to one poll, only 8% of the public say they "trust Congress." In a simple random sample of 10 people, what is the probability that at least one person "trusts Congress?"

• 0.188
• 0.378
• 0.434
• 0.566

I flip 3 coins. If I got heads on the first 2 coins, what is the probability that the 3rd flip is also a heads?

• 1/8
• 1/4
• 1/3
• 1/2

If P(A) = .25 and P(B) = .34, what is P(A u B) if A and B are independent?

• .085
• .505
• .590
• Insufficient Information

Suppose that the probability that an answer can be found on Google is .95, on Answers.com is .92, and on both websites is .874.  Are the possibilities of finding the answer on the two websites independent?

• Yes, because (.95)(.92) = .874
• No, because (.95)(.92) = .874
• Yes, because .95 ≥ .92 ≥ .874
• No, because 0.5(.95 + .92) ≠ .874

Given the three card shown:The cards are shuffled and a card is chosen.  It is replaced, reshuffled and another card is chosen. What is the probability at least one of the two cards chosen is odd?

• 1/3
• 4/9
• 5/9
• 1/9

The following Venn diagram uses the following definition. C = students taking calculus.  S = students taking statistics. What does the shaded region represent?

• students taking calculus
• students not taking statistics
• students taking calculus but not statistics
• students taking both calculus and statistics

If you choose a card at random from a well-shuffled deck of 52 cards, what is the probability that the card chosen is a red card or an ace?

• .5
• .538
• .577
• .615

A randomly selected student is asked to respond to the question, “Do you watch TV when you eat dinner?” The sample space is {always, often, seldom, never}. Which of the following represents a legitimate assignment of probabilities for this sample space?

• .25, .25, .25, .25
• .4, .3, .1, .2
• .5, .4, 0, .1
• all of these