
Concept explainers
(a)
To find: The probability for selecting a single person.
(a)

Answer to Problem 55E
Solution: Theprobability for selecting a single twitter user or personis 0.19.
Explanation of Solution
Given: According to Question 4.54, a random sample in which 19% are Twitter users who use Twitter to update their post or see another person's post.
Calculation: Consider the
Here, Y represents the Twitter user in the sample and N represents those users who do not use Twitter.
The probabilities for
(b)
To find: The probability for selecting three people.
(b)

Answer to Problem 55E
Solution: The probabilitiesare:
Explanation of Solution
Calculation: Consider the sample space (S) for choosing three person is,
The probabilities for sample space are,
(c)
To find: The probability for selecting a single person.
(c)

Answer to Problem 55E
Solution: The possible values are 0, 1, 2, 3 and their probabilities are 0.0069, 0.0876, 0.3741 and 0.5314 respectively.
Explanation of Solution
Calculation: Consider the sample space (S) for choosing three person is,
Here, T represents the Twitter user in the sample and Tc represents those users who do not use Twitter. Now, the sample space for the random variable X, which expresses the number of Twitter users in a
The probabilities for
Now, the probabilities are,
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Chapter 4 Solutions
Introduction to the Practice of Statistics: w/CrunchIt/EESEE Access Card
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