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Pergunta 1 0 em 1 pontos The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400. Note: For questions 19 and 20 you will need to use the Normal Table linked here Use the normal distribution as an approximation to the binomial distribution "multiple choice" question: select the correct answer. Which of the following is the correct justification for reliably using the normal approximation for X? Resposta Selecionada: n = 1600 ≥ 30 Resposta Correta: Both np = 1600 * 0.1 = 160 ≥ 10 and n(1 - p) = 1600 * 0.9 = 1440 ≥ 10 Pergunta 2 0 em 1 pontos The following three probability histograms represent the probability distributions of the random variables X, Y, and W. As is evident from the probability histograms, the mean of all three random variables is 5. Find the mean and variance of a discrete random variable, and apply these concepts for solving real world problems. "multiple choice" question: select the correct answer. Which of the three random variables has the largest standard deviation? Resposta Correta: X Pergunta 3 1 em 1 pontos An epidemiological study investigated the prevalence of two contagious diseases ( Disease 1 and Disease 2) in the U.S. Let A be the event that an individual contracts Disease 1 Let B be the event that an individual contracts Disease 2 Understand the reasoning behind the concept of conditional probability, calculate conditional probabilities and interpret them. "multiple choice" question: select the correct answer. What is the interpretation of P(B|A) in the context of this study? Resposta Selecionada: (D) and (E) are both interpretations of P(B|A). Resposta Correta: (D) and (E) are both interpretations of P(B|A). Feedback da resposta: This is correct. Pergunta 4 1 em 1 pontos Understand how probability quantifies uncertainty and relate the probability of an event to the likelihood of the event occurring. "multiple choice" question: select the correct answer. Which of the following is true regarding a probability of an event P(A)? Resposta Selecionada: 0≤P(A)≤1 Resposta Correta: 0≤P(A)≤1 Feedback da resposta: This is correct. The probability of an event can any number between 0 and 1, including 0 and 1. In other words, the probability of an event cannot be more than 1 or less than 0. Pergunta 5 0 em 1 pontos An epidemiological study investigated the prevalence of two contagious diseases ( Disease 1 and Disease 2) in the U.S. Let A be the event that an individual contracts Disease 1 Let B be the event that an individual contracts Disease 2 Understand the reasoning behind the concept of conditional probability, calculate conditional probabilities and interpret them. "multiple choice" question: select the correct answer. Of the individuals who did not contract Disease 2, what proportion will not contract Disease 1? Resposta Selecionada: .78 Resposta Correta: .78/.85 Pergunta 6 0 em 1 pontos Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods. "multiple choice" question: select the correct answer. 20% of all the students at a large university are international students. Two random samples of students are chosen; a random sample of n=64 students and a random sample of n=400 students. In which of the two samples is it more likely that more than 25% of the sampled students are international students? Resposta Selecionada: The sample of size n=400 since in there is more variability in the proportion of international students in larger samples. Resposta Correta: The sample of size n=64 since in there is more variability in the proportion of international students in smaller samples. Pergunta 7 1 em 1 pontos An epidemiological study reported the following information about two contagious diseases: · There is 15% chance of contracting Disease I · There is 20% chance of contracting Disease II · There is 2% chance of contracting both diseases Let A be the event that a randomly chosen person contracts Disease I Let B be the event that a randomly chosen person contracts Disease II Apply probability rules in order to find the likelihood of an event "multiple choice" question: select the correct answer. What does the probability P(A or B) mean in this context? Resposta Selecionada: The probability of contracting at least one of the two diseases Resposta Correta: The probability of contracting at least one of the two diseases Feedback da resposta: This is correct. P(A or B) is the probability of contracting Disease I or Disease II or both. In other words, P(A or B) is the probability of contracting at lease one of the two diseases. Pergunta 8 1 em 1 pontos Understand how probability quantifies uncertainty and relate the probability of an event to the likelihood of the event occurring. "multiple choice" question: select the correct answer. Let A be the event that a document will reach its destination on time using a certain service. If P(A)=.98 this means that: Resposta Selecionada: The document will almost always reach its destination on time Resposta Correta: The document will almost always reach its destination on time Feedback da resposta: This is correct. Pergunta 9 1 em 1 pontos Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods. "multiple choice" question: select the correct answer. Is it safe to assume that the sampling distribution of pˆ is approximately normal for random samples of size n=21? Resposta Selecionada: No, since n*p is not greater than 10. Resposta Correta: No, since n*p is not greater than 10. Feedback da resposta: This is correct. • Pergunta 10 0 em 1 pontos The probability table below summarizes the information that a large cable company provides about its customers: Where: T is the event that a randomly chosen customer subscribes to TV service I is the event that a randomly chosen customer subscribes to Internet service Create a probability table to organize and summarize information and use it to find probabilities "multiple choice" question: select the correct answer. What is the correct representation and probability of the event that a customer subscribes only to TV service? Resposta Selecionada: P(Not I) = .05 Resposta Correta: P(T and Not I) = .05