University of California, Los AngelesACC 471ch05 File: ch05, Chapter 5: Discrete Distributions

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1. Variables which take on values only at certain points over a given interval are called continuous random variables Ans: False Response: See section 5.1 Discrete versus Continuous Distributions ... Difficulty: Easy Learning Objective: 5.1: Define a random variable in order to differentiate between a discrete distribution and a continuous distribution. 2. A variable that can take on values at any point over a given interval is called a discrete random variable Ans: False Response: See section 5.1 Discrete versus Continuous Distributions Difficulty: Easy Learning Objective: 5.1: Define a random variable in order to differentiate between a discrete distribution and a continuous distribution. 3. The number of visitors to a website each day is an example of a discrete random variable Ans: True Response: See section 5.1 Discrete versus Continuous Distributions Difficulty: Easy Learning Objective: 5.1: Define a random variable in order to differentiate between a discrete distribution and a continuous distribution. 4. The amount of time a patient waits in a doctor's office is an example of a continuous random variable Ans: True Response: See section 5.1 Discrete versus Continuous Distributions Difficulty: Easy Learning Objective: 5.1: Define a random variable in order to differentiate between a discrete distribution and a continuous distribution. 5. The mean or the expected value of a discrete distribution is the long-run average of the occurrences. Ans: True Response: See section 5.2 Describing a Discrete Distribution Difficulty: Easy Learning Objective: 5.2: Determine the mean, variance, and standard deviation of a discrete distribution. 6. To compute the variance of a discrete distribution, it is not necessary to know the mean of the distribution. Ans: False Response: See section 5.2 Describing a Discrete Distribution Difficulty: Medium Learning Objective: 5.2: Determine the mean, variance, and standard deviation of a discrete distribution. 7. The variance of a discrete distribution increases if we add a positive constant to each one of its value. Ans: False Response: See section 5.2 Describing a Discrete Distribution Difficulty: Medium Learning Objective: 5.2: Determine the mean, variance, and standard deviation of a discrete distribution. 8. In a binomial experiment, any single trial contains only two possible outcomes and successive trials are independent. Ans: True Response: See section 5.3 Binomial Distribution Difficulty: Medium Learning Objective: 5.3: Solve problems involving the binomial distribution using the binomial formula and the binomial table. 9. In a binomial distribution, p, the probability of getting a successful outcome on any single trial, increases proportionately with every success. Ans: False Response: See section 5.3 Binomial Distribution Difficulty: Medium Learning Objective: 5.3: Solve problems involving the binomial distribution using the binomial formula and the binomial table. 10. The assumption of independent trials in a binomial distribution is not a great concern if the sample size is smaller than 1/20th of the population size. Ans: True Response: See section 5.3 Binomial Distribution Difficulty: Medium Learning Objective: 5.3: Solve problems involving the binomial distribution using the binomial formula and the binomial table. 11. For a binomial distribution in which the probability of success is p = 0.5, the variance is twice the mean. Ans: False Response: See section 5.3 Binomial Distribution Difficulty: Hard Learning Objective: 5.3: Solve problems involving the binomial distribution using the binomial formula and the binomial table. 12. The Poisson distribution is a continuous distribution which is very useful in solving waiting time problems Ans: False Response: See section 5.4 Poisson Distribution Difficulty: Easy Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 13. Both the Poisson and the binomial distributions are discrete distributions and both have a given number of trials. Ans: False Response: See section 5.4 Poisson Distribution Difficulty: Medium Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 14. The Poisson distribution is best suited to describe occurrences of rare events in a situation where each occurrence is independent of the other occurrences. Ans: True Response: See section 5.4 Poisson Distribution Difficulty: Easy Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 15. For the Poisson distribution the mean represents twice the value of the standard deviation.. Ans: False Response: See section 5.4 Poisson Distribution Difficulty: Easy Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 16. A binomial distribution is better than a Poisson distribution to describe the occurrence of major oil spills in the Gulf of Mexico. Ans: False Response: See section 5.4 Poisson Distribution Difficulty: Medium Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 17. For the Poisson distribution the mean and the variance are the same. Ans: True Response: See section 5.4 Poisson Distribution Difficulty: Easy Learning Objective: 5.4: Solve problems involving the Poisson distribution using the Poisson formula and the Poisson table. 18. Poisson distribution describes the occurrence of discrete events that may occur over a continuous interval of time or space. [Show More]

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