AP Stats Random Variables Practice

Suppose you pay $1.00 to roll a fair die with the understanding you will get $3.00 back rolling a 4 or a 2, and nothing otherwise.  What is the expected amount you win?

• $0.00
• -$1.00
• $1.00
• $3.00

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

Is your expected value always going to be what happens in real life?

• yes
• no

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.A.4

CCSS.HSS.MD.B.5

Which of the following is not a random variable?

• The heights of randomly-selected buildings in New York City.
• The suit of a card randomly-selected from a 52-card deck.
• The number of children in randomly-selected households in the United States.
• The amount of money won (or lost) by the next person to walk out of a casino in Las Vegas.

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CCSS.HSS.CP.A.1

A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day.  Based on the records, X has the following probability distribution.
The mean number of customers that make a purchase during the first hour that the store is open is:
   

• 2.0
• 2.5
• 2.9
• 3

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day.  Based on the records, X has the following probability distribution.
The standard deviation of the number of customers that make a purchase during the first hour that the store is open is

• 0.2
• 1.4
• 2.0
• 3.0

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CCSS.HSS.ID.A.2

CCSS.HSS.ID.A.3

CCSS.HSS.ID.A.4

The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school.What is the probability that exactly 2 of the first 20 blood donors have Type B blood? 

• 0.316
• 0.282
• 0.001
• Not here

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CCSS.HSS.CP.B.9

Barry Bonds has a career batting average of .298.  What is the probability that he will get on base 6 times in 10 at bats?

• 3.58%
• 5.46%
• 22.67%
• 100%

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CCSS.HSS.CP.B.9

The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. What is the probability that at least 2 of the first 10 blood donors has Type B blood? 

• 0.088
• 0.697
• 0.214
• 0.303 

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CCSS.HSS.CP.B.9

CCSS.HSS.MD.A.3

What does the p stand for in the binomial probability formula?

• Number of trials
• Number of Successes
• Probability of Successes
• Probability of Failures

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

A company states that 2% of its computers are returned for defects.  We take a sample of 100 computers to find the probability of 10 being defective.  Is this a binomial distribution?

• No because there is not a fixed number of trials.
• No because their are more than 2 outcomes.
• Yes since there are a fixed number of independent trials, outcomes in 2 categories, and the probability of defect is constant.
• No since computers would not be independent.

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CCSS.HSS.CP.A.2

CCSS.HSS.CP.A.3