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Study Resources (Statistics)

FREE RESPONSE QUESTIONS 1.Reports are often published that appear to conflict with earlier results, confusing the public and researchers alike. How can sample size play a role in this? 2.Reports are often published that appear to conflict with earlier results, confusing the public and researchers alike. How can a meta-analysis help address.
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  MULTIPLE CHOICE QUESTIONS 30.If 100 independent hypothesis tests are conducted using a significance level of 0.10, and if all of the null hypotheses are true, what is the expected number of false positives (type I errors)? a.0 b.5 c.10 d.There is not enough information to say. 31.Imagine you wish to test 4 independent hypotheses so that.
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  Multiple Choice QUESTIONS 38.Which of the following statements is true regarding the relationship between a Type I and Type II error in a given situation? a.Their probabilities add up to 1. b.A Type II error is two times as large as its corresponding Type I error. c.As the probability of one of them increases,.
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  FREE RESPONSE QUESTIONS 40.{Case study 27.10 narrative} The main implication by the researchers (and the media) about the results of this study is that if cities like Philadelphia would lower their hostility index, they would also lower their death rates. Is that a valid conclusion? Explain why or why not. 41.{Case study.
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  FREE RESPONSE QUESTIONS 33.The word ‘significant’ is often used to try to convince you that there is an important effect or relationship. Explain how this word can take on different meanings and how you need to be aware of that when consuming statistical information. 34.When it comes to sample size, “results may.
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  11.{Cell phone owners narrative} The frequency curve made from proportions of cell phone owners from the various samples of size 2,500 from this population will have what approximate mean and standard deviation? 12.{Cell phone owners narrative} What is the chance that a sample of size 2,500 from this population will contain.
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  FREE RESPONSE QUESTIONS 33.Explain in words what two errors you can make when drawing conclusions from a hypothesis test. 34.In the jury trial scenario, our null hypothesis is “innocent” and our alternative hypothesis is “guilty.” Explain which of the two potential errors is more serious, and justify your answer. 35.{Disease testing narrative} In.
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FREE RESPONSE QUESTIONS 1.{Case study 27.1 narrative} What do you think is the most interesting aspect of this study? 2.For Group 1, how might “acting out a dream (while dreaming)” be misinterpreted?   Multiple Choice QUESTIONS 3.{Case study 27.1 narrative} What type of study was this? a.A matched-pairs study. b.A prospective study. c.An observational study. d.A randomized experiment. FREE RESPONSE.
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FREE RESPONSE QUESTIONS 1.When you read the results of hypothesis tests in a newspaper, you are given very little information about the details of the test. What is often missing (name two things)? 2.Suppose you are told that “a relationship has been found between two variables” or that “a difference has been.
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  FREE RESPONSE QUESTIONS 11.Is it possible for the same relative risk to produce two different conclusions in two different statistical studies? Explain why or why not. (Assume data quality is not an issue.) 12.Explain how the public can be misled by the results of a “very large study.” (Assume data quality is.
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FREE RESPONSE QUESTIONS 1.How does the relative frequency interpretation of probability differ from the personal probability interpretation, in terms of variability in the results? 2.What can happen when a physical situation lends itself to computing a relative-frequency probability, but people ignore that information and go with their ‘intuition’? FREE RESPONSE QUESTIONS 3.In what sense.
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  FREE RESPONSE QUESTIONS 21.{Oranges narrative} What percentage of all the bags in the entire shipment do you think are underweight? Give the most complete answer you can. 22.{Oranges narrative} What is the margin of error for a 95% confidence interval for the proportion of bags in the shipment that are underweight? 23.{Oranges narrative}.
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  FREE RESPONSE QUESTIONS 8.{Case study 27.3 narrative} The researchers seem to be saying (or at least implying) that moving is the cause of these problems. Is that an appropriate conclusion? Explain. 9.{Case study 27.3 narrative} Name one of the confounding factors not controlled for in this study. 10.{Case study 27.3 narrative} Discuss how.
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  FREE RESPONSE QUESTIONS 27.Give two tips for improving someone’s personal probabilities and judgments. 28.The first step in making a decision based on a probability you are given is to make sure the probability is not distorted. Explain why this is such an important step. Multiple Choice QUESTIONS 29.Which of the following statements is true? a.Excess.
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  FREE RESPONSE QUESTIONS 23.Name two of the eleven components of the Index of Leading Economic Indicators. 24.Explain the difference between a leading economic indicator and a lagging economic indicator. Multiple Choice QUESTIONS 25.Which of the following does not describe the Index of Leading Economic Indicators? 26.Which of the following is not a type of economic.
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  FREE RESPONSE QUESTIONS 13.Which of the following sequences of six tosses of a fair coin is more likely (if either): HTHTTH, or HHHTTT? Explain your answer. 14.Do you agree with the following statement regarding sequences of tosses of a fair coin? Explain why or why not. “The sequence HHHHTH doesn’t represent the.
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  FREE RESPONSE QUESTIONS 13.Describe a general scenario where you would use a confidence interval for the difference between two means. 14.How should you collect your data in order to use it in a confidence interval for the difference of two means? 15.{Cell phone use narrative} Based on these sample results, what is the.
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FREE RESPONSE QUESTIONS 1.What two pieces of information do you get from a confidence interval that can help you evaluate whether or not statistically results are really important to you? 2.Explain the difference between the statistical meaning of the word ‘significant results’ and the regular conversational meaning of the word ‘significant results.’ 3.Suppose.
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  FREE RESPONSE QUESTIONS 23.Journal articles often report means and standard deviations, and they also often report their results in the form (mean +/− standard deviation). Does this latter form represent a real confidence interval for the population mean? If yes, explain why. If not, tell what it does represent. (Assume the.
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  FREE RESPONSE QUESTIONS 29.{Test scores narrative} Suppose you take numerous random samples of size 100 from this population. Describe the shape and give the mean and standard deviation of the resulting frequency curve. 30.{Test scores narrative} Suppose you take a single random sample of size 100 people from this population. What is.
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  FREE RESPONSE QUESTIONS 18.{Case study 27.5 narrative} The survey was commissioned by Canon U.S.A., maker of office copiers and printers that claim to cut the time and money “spent running from one machine to the next.” In what way might this cause a problem for the results of the study? 19.{Case study.
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  FREE RESPONSE QUESTIONS 11.Give an example of a confidence interval for a proportion with a margin of error of 5% that falls below zero for some of its values. 12.Name two different situations that can result in a confidence interval for a proportion falling into negative numbers for some of its values.
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FREE RESPONSE QUESTIONS 1.When researchers conduct a hypothesis test, what general question is being asked and answered regarding the sample versus the population?   For Questions 2-5, use the following narrative Narrative: Cell phone survey Suppose you suspect that most people are unhappy with their cell phone plans. You conduct a survey of 400 randomly.
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  FREE RESPONSE QUESTIONS   For Questions 1-2, use the following narrative Narrative: Bananas Suppose a researcher asks the question: What is the average weight of bananas selected for purchase by customers in grocery stores? Assume the distribution of weights is the same across all stores. 1.{Bananas narrative} How can the researcher go about answering this.
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  Multiple Choice QUESTIONS 15.Suppose a survey was conducted to find out what proportion of Americans intend to vote in the next Presidential election. For which of the following confidence intervals would it be fair to conclude, with high confidence, that a majority of Americans will vote in the next Presidential election? a.52%.
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  FREE RESPONSE QUESTIONS 15.What is ‘data snooping’ and why is it a practice to be avoided? 16.How is it possible that two different statistical analyses of the same data set can produce different results and more importantly, different conclusions? Multiple Choice QUESTIONS 17.When should a researcher decide whether an alternative hypothesis should be one-sided.
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  FREE RESPONSE QUESTIONS 31.Are all confidence intervals (whether they be for population means, proportions, or anything else) symmetric around their respective sample values? Explain. 32.{Side effects narrative} These confidence intervals are not in the usual format of ‘sample value plus or minus the margin of error’ that we have seen. Explain how.
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  Multiple Choice QUESTIONS 10.What do we call a hypothesis test when the alternative hypothesis includes a possible difference in either direction? a.A two-direction test. b.A two-sided test. c.A test that is not possible to conduct. d.None of the above. 11.Suppose the p-value for your hypothesis test for a difference of two means was .001. Which of.
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FREE RESPONSE QUESTIONS 1.What three items are needed in order to construct a confidence interval to estimate the mean of a population? 2.The formula for a confidence interval for the population mean is based on the rule for sample means, which has assumptions that need to be met. What are those assumptions?.
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  17.One problem of meta-analysis is that two different studies may involve subtle differences in treatments but call the treatments by the same name. Give an example. 18.What is meant by the ‘file drawer problem’ regarding meta-analysis? 19.If the statistically significant studies of a relationship are the ones that are more likely to.
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  FREE RESPONSE QUESTIONS 22.Name two ways in which statistical results can be unfairly reported by researchers or the media. 23.Explain the ethical dilemma faced by a researcher when he/she is trying to determine what sample size to use in his/her study. 24.Suppose a researcher conducts 100 hypothesis tests on her large data set.
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  Multiple Choice QUESTIONS 17.Which of the following is the correct way to calculate the standard error of the difference between two (independent) means? Let SEM1 represent the standard error of the first mean, and let SEM2 represent the standard error of the second mean. a.SEM1 + SEM2 b.SEM1 − SEM2. c.The square root of.
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  FREE RESPONSE QUESTIONS 27.If the bookmakers who run sports betting operations were to set fair odds, so that both the house and those placing bets had expected values of zero, then the probabilities for all of the players should sum to 1, but they don’t. Do they sum to a higher.
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  18.Explain how the natural variability in the population can affect a test’s ability to detect a difference or relationship in the population that actually does exist. 19.Suppose a company says they deliver their packages in 2 days or less, on average, and you are concerned that the packages are taking longer.
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  Multiple Choice QUESTIONS 21.In which of the following situations does the rule for sample proportions apply? a.A pollster takes a random sample of 1,000 Americans and asks their opinion on the President (approve/disapprove/neutral). He is interested in the percentage who approve of the President. b.You want to know whether or not people like.
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  FREE RESPONSE QUESTIONS 11.Name two benefits of meta-analysis. 12.Name one way in which a meta-analysis improves the situation where many small studies were conducted, but no large studies. Multiple Choice QUESTIONS 13.Which of the following can be a direct benefit of a meta-analysis for future research? a.Designing better experiments. b.A change in the focus of the.
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  FREE RESPONSE QUESTIONS 14.{Case study 27.4 narrative} When the pool of studies examined was reduced to include only those following any type of surgery, the results were still found to be statistically significant. Yet when the pool of studies was reduced a third time, to include only those studies that followed.
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  FREE RESPONSE QUESTIONS 30.{Case study 27.8 narrative} The p-value for testing the difference in infant weight gain for the exercise group versus the control group over the time of the study was found to be .86. Explain, in terms that a non-statistics student would understand, what this p-value means. 31.{Case study 27.8.
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FREE RESPONSE QUESTIONS 1.Explain (in words that a non-statistics student would understand) what is meant by a ‘95% confidence interval.’ 2.Explain what it would take in order to construct a 100% confidence interval and why that is not usually a feasible option. 3.Statisticians have a phrase, “Being a statistician means never having to.
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  Multiple Choice QUESTIONS 38.Which of the following are examples where you would be interested in estimating the population mean? a.About how long do left-handed people live? b.Do most people support or oppose the President’s foreign policy? c.What size was the viewing population who tuned in to the ABC News special last night? d.All of the.
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FREE RESPONSE QUESTIONS 1.Name three things that psychologists are supposed to inform participants about when obtaining informed consent, according to the American Psychological Association’s code of ethics. Answer:  many possible answers, including any three of the following: 1) the purpose of the research; 2) the procedures to be used; 3) the.
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  FREE RESPONSE QUESTIONS 15.Name two major criticisms of the Consumer Price Index (CPI). 16.One criticism of the CPI is that the market basket used in the CPI may not reflect current spending priorities. Why does this problem occur? Multiple Choice QUESTIONS 17.What do economists believe about the CPI? a.It underestimates increases in the cost of.
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  FREE RESPONSE QUESTIONS 11.In the American judicial system, you must presume that the defendant is innocent unless there is enough evidence to conclude that he/she is guilty. What are the null and alternative hypotheses in this situation? Be sure to label which one is which. 12.Suppose the jury determines that the evidence.
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  FREE RESPONSE QUESTIONS 43.Name the two basic techniques researchers use to summarize and draw conclusions about a population based on their statistical results from a sample. 44.Suppose you do not know anything about what the true population mean is, and you want to estimate it using a sample mean. Which statistical technique.
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  Multiple Choice QUESTIONS 26.Which of the following statements is true regarding a 95% confidence interval? Assume numerous large samples are taken from the population. a.In 95% of all samples, the sample proportion will fall within 2 standard deviations of the mean, which is the true proportion for the population. b.In 95% of all.
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  FREE RESPONSE QUESTIONS 16.Journal articles very often report the p-value for their results, rather than just stating their conclusions as to whether or not they found a statistically significant result. Explain why this is important to you as an educated consumer of statistical information. 17.{Math pass narrative} Explain what these results mean.
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  FREE RESPONSE QUESTIONS 7.Name a situation where the quality of data becomes an ethical issue. 8.Explain why it would not be ethical to report the sample size of a survey without also reporting the percentage or number of people who responded to it. 9.Give two benefits of computer-assisted information collection (versus other methods). 10.Explain.
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  FREE RESPONSE QUESTIONS 22.{Coupons narrative} Write down the null and alternative hypotheses. 23.{Coupons narrative} Explain whether this is a one-sided or a two-sided test, and why. 24.{Coupons narrative} What is the value of the test statistic for your observed results? 25.{Coupons narrative} What is the p-value for your observed results? 26.{Coupons narrative} What is your.
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  FREE RESPONSE QUESTIONS 26.{Case study 27.7 narrative} This is an excellent example of a survey where wording of the questions can greatly affect the results. Comment on the wording of the question, “Do you approve or disapprove of force-feeding geese to make their livers swell up to produce pate for restaurants?”.
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