EBook Problems Distrib RV

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:''(d) 2.3
:''(d) 2.3
{{hidden|Answer|(b)}}
{{hidden|Answer|(b)}}
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===Problem 4===
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The manager of a stock room in a factory knows from her study of records that the daily demand for a certain tool has the following probability model:
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{|border="1"
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| Demand || 0 || 1 || 2
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|-
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| Probability || 0.1 || 0.5 || 0.4
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|}
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Suppose it costs the factory $10 each time the tool is used. Find the variance of the daily cost of using the tool.
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*Choose one answer.
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:''(a) 13
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:''(b) 41
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:''(c) 1.3
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:''(d) 10
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{{hidden|Answer|(b)}}
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<hr>

Current revision as of 23:34, 28 December 2008

Contents

EBook Problems Set - Random Variables

Problem 1

The probability model below describes the number of repair calls that an appliance repair shop may receive during an hour:

Repair calls 0 1 2 3
P(x) 0.1 0.3 0.4 0.2

The probability that the number of repair calls is at least 2 is:

  • Choose one answer.
(a) 0.8
(b) 0.2
(c) 0.4
(d) 0.6


Problem 2

In a litter of seven kittens, three are female. You pick two kittens at random. The probability model for the number of male kittens is:

Number males 0 1 2
Probability 0.143 0.571 0.286

The expected number of males is:

  • Choose one answer.
(a) 0.64
(b) 1.7
(c) 1.14
(d) 2.1


Problem 3

Let X represent a discrete random variable that takes any of the values and probabilities given below:

X -2 5 6
P(X) 0.4 0.4 __

The probability for X = 6 is missing. What is it?

  • Choose one answer.
(a) It cannot be determined from the information given
(b) 0.2
(c) 0.6
(d) 2.3


Problem 4

The manager of a stock room in a factory knows from her study of records that the daily demand for a certain tool has the following probability model:

Demand 0 1 2
Probability 0.1 0.5 0.4

Suppose it costs the factory $10 each time the tool is used. Find the variance of the daily cost of using the tool.

  • Choose one answer.
(a) 13
(b) 41
(c) 1.3
(d) 10





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