Chapter 5: Problem 1
Explain the meaning of a random variable, a discrete random variable, and a continuous random variable. Give one example each of a discrete random variable and a continuous random variable.
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Chapter 5: Problem 1
Explain the meaning of a random variable, a discrete random variable, and a continuous random variable. Give one example each of a discrete random variable and a continuous random variable.
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Although Microsoft Windows is the primary operating system for desktop and laptop PC computers, Microsoft's Windows Phone operating system is installed in only \(1.6 \%\) of smartphones (www. latimes.com/business/la-fi-google- mobile-20110817,0,6230477.story). a. Assuming that \(1.6 \%\) of all current smartphones have Microsoft's Windows Phone operating system, using the binomial formula, find the probability that the number of smartphones in a sample of 80 that have Microsoft's Windows Phone operating system is i. exactly 2 ii. exactly 4 b. Suppose that \(5 \%\) of all current smartphones have Microsoft's Windows Phone operating system. Use the binomial probabilities table (Table I of Appendix C) or technology to find the probability that in a random sample of 20 smartphones, the number of smartphones that have Microsoft's Windows Phone operating system is i. at most 2 ii. 2 to 3 iii. at least 2
One of the four gas stations located at an intersection of two major roads is a Texaco station. Suppose the next six cars that stop at any of these four gas stations make their selections randomly and independently. Let \(x\) be the number of cars in these six that stop at the Texaco station. Is \(x\) a discrete or a continuous random variable? Explain. What are the possible values that \(x\) can assume?
Although Borok's Electronics Company has no openings, it still receives an average of \(3.2\) unsolicited applications per week from people seeking jobs. a. Using the Poisson formula, find the probability that this company will receive no applications next week. b. Let \(x\) denote the number of applications this company will receive during a given week. Using the Poisson probabilities table from Appendix \(\mathrm{C}\), write the probability distribution table of \(x\). c. Find the mean, variance, and standard deviation of the probability distribution developed in part \(\mathrm{b}\).
According to the Alzheimer's Association (www.alz.org/documents_custom/2011_Facts_Figures Fact_Sheet.pdf), \(3.7 \%\) of Americans with Alzheimer's disease were younger than the age of 65 years in 2011 (which means that they were diagnosed with early onset of Alzheimer's). Suppose that currently \(3.7 \%\) of Americans with Alzheimer's disease are younger than the age of 65 years. Suppose that two Americans with Alzheimer's disease are selected at random. Let \(x\) denote the number in this sample of two Americans with Alzheimer's disease who are younger than the age of 65 years. Construct the probability distribution table of \(x\). Draw a tree diagram for this problem.
An average of \(.8\) accident occur per day in a particular large city. a. Find the probability that no accident will occur in this city on a given day. b. Let \(x\) denote the number of accidents that will occur in this city on a given day. Write the probability distribution of \(x\). c. Find the mean, variance, and standard deviation of the probability distribution developed in part b.
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