statistics 8: chapters 7 to 10, sample multiple choice questions, Exams of Statistics

Download statistics 8: chapters 7 to 10, sample multiple choice questions and more Exams Statistics in PDF only on Docsity! STATISTICS 8: CHAPTERS 7 TO 10, SAMPLE MULTIPLE CHOICE QUESTIONS 1. If two events (both with probability greater than 0) are mutually exclusive, then: A. They also must be independent. B. They also could be independent. C. They cannot be independent. 2. If two events (both with probability greater than 0) are mutually exclusive, then: A. They also must be complements. B. They also could be complements. C. They cannot be complements. 3. Suppose that the probability of event A is 0.2 and the probability of event B is 0.4. Also, suppose that the two events are independent. Then P(A|B) is: A. P(A) = 0.2 B. P(A)/P(B) = 0.2/0.4 = ½ C. P(A) × P(B) = (0.2)(0.4) = 0.08 D. None of the above. 4. Which of the following is an example of a relative frequency probability based on measuring a representative sample and observing relative frequencies of possible outcomes? A. According to the late Carl Sagan, the probability that the earth will be hit by a civilization- threatening asteroid in the next century is about 0.001. B. If you flip a fair coin, the probability that it lands with heads up is ½. C. Based on a recent Newsweek poll, the probability that a randomly selected adult in the US would say they oppose federal funding for stem cell research is about 0.37. D. A new airline boasts that the probability that its flights will be on time is 0.92, because 92% of all flights it has ever flown did arrive on time. 5. Which of the following statements best describes the relationship between a parameter and a statistic? A. A parameter has a sampling distribution with the statistic as its mean. B. A parameter has a sampling distribution that can be used to determine what values the statistic is likely to have in repeated samples. C. A parameter is used to estimate a statistic. D. A statistic is used to estimate a parameter. 6. A sampling distribution is the probability distribution for which one of the following: A. A sample B. A sample statistic C. A population D. A population parameter 7. Which of the following is the most common example of a situation for which the main parameter of interest is a population proportion? A. A binomial experiment B. A normal experiment C. A randomized experiment D. An observational study 8. Which statement is not true about confidence intervals? A. A confidence interval is an interval of values computed from sample data that is likely to include the true population value. B. An approximate formula for a 95% confidence interval is sample estimate ± margin of error. C. A confidence interval between 20% and 40% means that the population proportion lies between 20% and 40%. D. A 99% confidence interval procedure has a higher probability of producing intervals that will include the population parameter than a 95% confidence interval procedure. 9. Which statement is not true about the 95% confidence level? A. Confidence intervals computed by using the same procedure will include the true population value for 95% of all possible random samples taken from the population. B. The procedure that is used to determine the confidence interval will provide an interval that includes the population parameter with probability of 0.95. C. The probability that the true value of the population parameter falls between the bounds of an already computed confidence interval is roughly 95%. D. If we consider all possible randomly selected samples of the same size from a population, the 95% is the percentage of those samples for which the confidence interval includes the population parameter. 10. In a random sample of 50 men, 40% said they preferred to walk up stairs rather than take the elevator. In a random sample of 40 women, 50% said they preferred the stairs. The difference between the two sample proportions (men – women) is to be calculated. Which of the following choices correctly denotes the difference between the two sample proportions that is desired? A. 10.021 =− pp B. 10.0ˆˆ 21 =− pp C. 10.021 −=− pp D. 10.0ˆˆ 21 −=− pp <-Correct answer 11. Which of the following statements is correct about a parameter and a statistic associated with repeated random samples of the same size from the same population? A. Values of a parameter will vary from sample to sample but values of a statistic will not. B. Values of both a parameter and a statistic may vary from sample to sample. C. Values of a parameter will vary according to the sampling distribution for that parameter. D. Values of a statistic will vary according to the sampling distribution for that statistic. 12. Five hundred (500) random samples of size n=900 are taken from a large population in which 10% are left-handed. The proportion of the sample that is left-handed is found for each sample and a histogram of these 500 proportions is drawn. Which interval covers the range into which about 68% of the values in the histogram will fall? A. .1 ± .010 B. .1 ± .0134 C. .1 ± .0167 D. .1 ± .020