R Exercise #2

Requirements

1. Complete the assignment in R and submit your R file. In your R file, please
2. clearly indicate which question you are answering with your R code.
3. You may find the following resources helpful:

• Elementary Statistics with R (http://www.r-tutor.com/elementary- statistics).
• oMostRrelatedproblemsfollowthisRtutorial.
• oInadditiontotheRTutorialvideoforbeginners(Seeblackboard),the
• section "R Introduction" will give you a starting point for learning R.
• https://www.youtube.com/watch?v=VGKz3Jkx-9I&t=326s(This video
• helps with joint frequency distribution, a.k.a. cross-tabulation or contingency table).

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Problem 3

Market-share-analysis company Net Applications monitors and reports on Internet browser usage. According to Net Applications, Google's Chrome browser exceeded a 20% market share for the first time, with a 20.37% share of the browser market. For a randomly selected group of 20 Internet browser users, answer the following questions.

1. Compute the probability that exactly 8 of the 20 Internet browser users use Chrome as their Internet browser.
2. Compute the probability that at least 3 of the 20 Internet browser users use Chrome as their Internet browser.
3. For the sample of 20 Internet browser users, compute the expected number, the variance and standard deviation of the number of Chrome users.

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Problem 4

Over 500 million tweets are sent per day. Assume that the number of tweets per hour follows a Poisson distribution and that Bob receives on average 7 tweets during his lunch hour.

1. What is the probability that Bob receives no tweets during his lunch hour?
2. What is the probability that Bob receives at least 4 tweets during his lunch hour?
3. What is the expected number of tweets Bob receives during the first 30 minutes of his lunch hour? What is the probability that Bob receives no tweets during the first 30 minutes of his lunch hour?

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Problem 5

1. What is the probability that a household views television more than 3 hours a day?
2. What is the probability that a household spends 5 - 10 hours watching television more a day?
3. How many hours of television viewing must a household have in order to be in the top 3% of all television viewing households?

Television viewing reached a new high when the Nielsen Company reported a mean

daily viewing time of 8.35 hours per household. Use a nor

mal probability

distribution with a standard deviation of 2.5 hours to answer the following

questions about daily television viewing per household.

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Problem 6

Comcast Corporation is the largest cable television company, the second largest

Internet service provider, and the fourth largest telephone service provider in the

United States. Generally known for quality and reliable service, the company

periodically experiences unexpected service interruptions. On January 14, 2014,

such an interruption occurred for the Comcast customers living in southwest

Florida. When customers called the Comcast office, a recorded message told them

that the company was aware of the service outage and that it was anticipated that

service would be restored in two hours. Assume that two hours is the mean time to

do the repair and that the repair time has an exponential probability distribution.

1. What is the probability that the cable service will be repaired in one hour or less?
2. What is the probability that the repair will take between one hour and two hours?
3. For a customer who calls the Comcast office at 1:00 p.m., what is the probability that the cable service will not be repaired by 5:00 p.m.?