Unit 6 Quiz Probability Distribution and Expected Value

Given the probability model in the table below, what is the expected value of the random variable?
  X        50          20        5
P(X)     0.1         0.3      0.6

• 14
• 4.67
• 5
• 7.5

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

Is this a probability distribution?

• No

• Yes

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CCSS.HSS.MD.A.1

CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.A.4

Is this a probability distribution?

• No
• Yes

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CCSS.HSS.MD.A.1

CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

The table represents the probability of guessing correct on a 5 question true-false quiz.  Find the probability for at least 4 questions correct.

• .03125
• .15625
• .3125
• .1875

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CCSS.HSF-LE.A.1C

A fair, 6-sided dice is thrown 120 times.

Roughly how many times would you expect the number 5 to come up?

• 6

• 10

• 12

• 20

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

A fair, 6-sided dice is thrown 18 times.

Roughly how many times would you expect the number 6 to come up?

• 1

• 3

• 6

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

Sam’s pencil case contains 3 red, 2 blue and 5 black pens.

He takes a pen out without looking then puts it back 100 times.

Roughly how many times would you expect him to pick up a red pen?

• 10

• 20

• 30

• 50

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CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

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CCSS.HSS.MD.A.1

CCSS.HSS.MD.A.3

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

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CCSS.HSS.MD.A.1

A marketing survey compiled data on the number of cars in households.  If X = the number of cars in a randomly selected household, and we omit the rare cases of more than 5 cars, then X has the following probability distribution: 
X           0          1          2          3           4           5    
P(X)   0.24    0.37    0.20    0.11    0.05     0.03
What is the probability that a randomly chosen household has at least two cars?

• 0.20
• 0.29
• 0.39
• 0.61

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CCSS.HSS.CP.A.1

CCSS.HSS.CP.B.7

CCSS.HSS.MD.A.1