STA 210 Exam 1 (Quizzes)
Consider the following survey question: "The Mac operating system rarely gets infected by viruses and therefore Department of Education should only purchase Mac computers. Please answer Yes or No". What is one objection to this question, as asked? A. Because of the "rarely gets infected by viruses" clause this question is a leading question. B. It won't necessarily be clear what one means by a Mac operating system." C. Only have two possible answers severely limits the breadth of expression for the respondent. D. It would be silly to ask this question to people who don't have any purchasing power in the College of Education. (Quiz 5)
A
Please read the following excerpt a 2006 CNN/USA Today/Gallup poll. Suppose CNN/USA Today/Gallup had wanted to produce a 99.9% confidence interval that had a width of 0.02 (or 2%). What size sample would they have needed to take in order for this to happen? A. 27,060 B. 6,765 C. 2,500 D. 10,000 (Quiz 9)
A
Recall Harris Poll disclaimer mentioned in the Read All About It (or the video). Harris is a major polling organization that refuses to accompany their poll reports with a margin of error. What is one reason that was given for such a bold omission? A. Harris recognizes that there are many sources of error that are not addressed by the MOE, so reporting it might be misleading. B. Harris claims that poll participation rates are so high that the MOE doesn't add anything useful. C. Harris claims that publication sponsors simply don't want to see the MOE reported any longer. D. Harris recognizes that the MOE is simply too difficult to calculate, so why bother. (Quiz 10)
A
Refer to the graphic below. We encountered this summary of the sampling distribution of the sample proportion in class. Specify an interval (range) in which 68% of all sample proportions based on samples of size n could be expected to occur. A. Within (0.5)x(1/sqrt(n)) on either side of the parameter p. B. Within (1/sqrt(n)) on either side of the sample proportion phat. C. Within (0.5)x(1/sqrt(n)) on either side of the sample proportion phat. D. Within (1/sqrt(n)) on either side of the parameter p. (Quiz 9)
A
Suppose you have a data set with 1000 observations in it. 500 of those are all 5 and 500 are 15. Then the standard deviation is about? A. About 5 B. 2.51 C. Can't tell from information given D. About 25 (Quiz 3)
A
Suppose you have a data set with 1000 observations in it. 500 of those are all 5 and 500 are 15. What of the following are true? A. The mean and median are the same B. The mean is bigger than the median C. The mean is smaller than the median D. The mean is 0 (Quiz 3)
A
The claim has been made that over 4 million women in the U.S. are battered to death each year by a spouse or boyfriend. What is wrong with this claim? A. Only about 2.4 million people die in the U.S. each year from all causes. B. Only about 300,000 people die in the U.S. each year from all causes. C. Only about 2.4 thousand people die in the U.S. each year from all causes. D. Only about 4 million people die in the U.S. each year from all causes. (Quiz 1)
A
The distribution shown here represents the sampling distribution that resulted from 44 simple random samples, each of size 50, taken from a manufactured population of 250 voters. In each case the proportion of sampled voters who agreed the government was doing enough about the problem of rabid squirrels was recorded. About what percentage of the time did a sample percentage between 21% and 36% occur? A. 80% B. 84% C. 45% D. 50% (either it did or it didn't) (Quiz 8)
A
What are the two keys to having confidence in your parameter estimate? A. The probabilistic nature of the sample selection, and some neat mathematics that follow from this. B. Knowing that you did a good job, and understanding the population context. C. Always being upbeat when interviewing subjects and avoiding confounding variables. D. Making sure your sample is representative of your population, and making sure you are able to do the subsequent computations with integrity. (Quiz 4)
A
What can one say about the sampling distribution of a sample statistic based on a simple random sample? A. It is about bell-shaped and peaks above the parameter B. It is usually skewed if the population concerns incomes C. It will be roughly a straight line D. Nothing can be said in advance about the sampling distribution since the sampling was random (Quiz 6)
A
What do we mean by "human inference?" A. Off-hand phrase taken to mean inference we make from statistical constructs. B. Off-hand phrase taken to mean "statistically significant." C. Off-hand phrase taken to mean that humans, not lab animals, were the experimental subjects. D. Off-hand phrase taken to mean basic numeracy. (Quiz 1)
A
What is "response substitution?" A. This is the tendency for survey respondents to present their answers in a way that allows them to express their opinions about other issues that aren't the topic of the survey. B. This is the desire of the interviewee to be looked at favorably by the interviewer and, as such, will purposely conform to social norms. C. This is the threat of being stereotyped or confirming a negative stereotype. D. This is the tendency for survey respondents to substitute questions for those that are worded poorly or are hard to understand. (Quiz 5)
A
What is a non-sampling error? A. An error caused by something other than the fact that a sample was selected instead of the entire population B. Error due to non-sampling random fluctuation C. An error caused by the fact that something other than a sample was taken D. Error due to sampling variability (Quiz 10)
A
Which of the following statements do you think could possibly be true? A. The number of students enrolled at Midville University decreased by 10.4% last year. B. A basketball team took 20 free throws in a game last week and made 72.6% of them. C. Yesterday it was 30° (Fahrenheit) in Chicago. Today it warmed up to 60°. This is a 50% increase in the temperature. D. My weight decreased by 10% last year but then increased by 10% in the first two months of this year. Thus, my overall weight from the beginning of last year until now is unchanged. (Quiz 1)
A
You ask a question to a random sample of 1000 adults in Texas (population 18 million people) and to a separate random sample of 1000 adults in Indiana (population 5.7 million people). You make separate 95% confidence statements about the percent of all adults in each state who agree. Your margin of error for Indiana is: A. the same as in Texas, because the two samples are the same size. B. larger than in Texas, because there are fewer people in Indiana. C. smaller than in Texas, because there are fewer people in Indiana. D. either smaller or larger than in Texas, because the sample result varies due to chance. (Quiz 6)
A
A population has 50 items, 21 green and 29 red. Turns out there are 2118760 possible samples of size 5 that can be taken from this population. Suppose you computed the sample proportion of green in each of these 2118760 samples of size 5 and added them all up. What would you get? A. 21/50 B. 889879.2 C. 29/50 D. 1228880.8 (Quiz 5)
B
Are you numerate? Here's a question from the workbook that will help you decide. An article entitled "Cocaine Floods the Playground: Use of the Addictive Drug by Children Doubles in a Year" appeared in 2006 in The Times. Here is an excerpt of what the authors said "Cocaine use among children has doubled in a year as the fashionable drug of the middle classes extends its reach from the dinner party to the playground. Hundreds of thousands of 11 to 15-year-olds are being offered the Class A drug .... Figures published yesterday showed that cocaine use among 11 to 15-year-olds doubled from 1 percent to 2 percent between 2004 and 2005." Where did the justification for use of the word doubled likely come from? A. 1.9/1.4 is about 1.8 which rounds to 2 B. 1.9 is about 2 and 1.4 is about 1 so that is likely the source for the word "doubles." C. 1.4 truncates to .4 and 1.9 truncates to .9 and .9 is just a little more than double .4 D. 1.9 in 2005 rounds to 2, so produces the justification for saying "doubles." (Quiz 2)
B
In a 2012 Gallup poll, eighty-two percent of adult U.S. Catholics say birth control is morally acceptable. Results for this poll are based on telephone interviews conducted May 3-6, 2012, with a random sample of 1,024 adult Catholics, aged 18 and older, living in all 50 U.S. states and the District of Columbia. What is the corresponding 95% confidence interval for the proportion of all adult U.S. Catholics who feel birth control is morally acceptable? A. 0.82 plus or minus 3% B. 82% plus or minus 3% C. 0.82 plus or minus 0.001 D. There are two correct answers listed here. (Quiz 6)
B
In the New York Times Magazine, Tara Parker-Pope makes the case that teenagers are more conservative than their parents were. For example, the fraction of high-school seniors who reported that they had recently consumed alcohol fell from 72% in 1980 (illustrated as the big one-gallon - 128 ounce - jug) to 40% in 2011 (illustrated as the little 8-ounce glass). The actual percent "Parents" consumption divided by percent "Kids" consumption is approximately ___ but the graphic makes that ratio look more like ___. The two best answers for filling in these blanks (in respective order) are: A. 1.8 and 1.6 B. 1.8 and 16 C. 32 and 120 D. 32 and 1.6 (Quiz 1)
B
In the piece on Deathly Hallow's book sales, it was claimed that more than 50,000 were sold per minute on the average. What was wrong with this figure? A. 300,000 were sold on average each hour. That means only 500 were sold per minute. Decimal error. B. 300,000 were sold on average each hour. That means only 5000 were sold per minute. Decimal error. C. 300,000 were sold on average each hour. 300,000/60 = 50,000 so nothing is wrong with the number reported in the piece. The reviewer of the article who brought this up was just mistaken. D. 600,000 were sold on average per hour. That means that 10,000 were sold per minute, not 50,000. Arithmetic mistake. (Quiz 2)
B
Refer to Question 1. What is the likely "human inference" and what is the "statistical construct" that is being used to produce it? A. Human inference is that cocaine use is out of control and the statistical construct is the 1.4. B. Human inference is that cocaine use is out of control and the statistical construct is the ratio 2-to-1. C. Human inference is that the ratio is for all practical purposes 2-to-1 and statistical construct is the evidence that cocaine use is out of control. D. Human inference is that the ratio is in reality 1.9 to 1.4 and the statistical construct is that cocaine use is not as bad as the headline says. (Quiz 2)
B
The well-respected journal Science, in an article on insects and plants, mentioned a California field that produced 750,000 melons per acre. How do you react to that? It may help you know that an acre is 43,560 square feet. A. This is reasonable, suggesting about 1.7 melons per square foot B. This is unreasonable, suggesting about 17 melons per square foot C. This is reasonable, suggesting about 5.8 melons per square foot D. This is unreasonable, suggesting about only 0.05 melons per square foot (Quiz 1)
B
What happens to the margin of error as the sample size gets larger? A. It will depend on the sample B. It decreases C. It stays the same D. It increases (Quiz 7)
B
What is a simple random sample? A. A sample chosen in such a way that you can be sure that subject characteristics (e.g. "male" and "female") will perfectly reflect the population. B. A sample chosen in such a way that all samples of that same size have the same chance of being chosen. C. A sample chosen in such a way that all samples of that same size have some chance of being chosen. D. A sample chosen in such a way that any given individual in the population has a 50-50 chance of being included (that is, either she is included or she is not). (Quiz 4)
B
What is the goal of sampling? A. To make inferences about a sample from what we know about our population. B. To make inferences about a population from what we know about our sample. C. To make inferences about a statistic that is unknown. D. To make inferences about a topic that is not numerical, and hence not calculable. (Quiz 4)
B
Which of the following are examples of strategies for reducing non-sampling errors? A. Use of technology-assisted confidential interview techniques B. All of those listed here C. Awareness of psychology of question order D. Use of inducements for non-responders (Quiz 10)
B
A 1996 Gallup poll of eligible New Hampshire primary voters reported that "of 1200 voters surveyed, 24% would vote for Senator Bob Dole if the primary election were held today". The Gallup organization also reported that the margin of error for a sample of 1200 people is 3 percentage points. If the Gallup organization had wanted to make a confidence statement based on the same data, only with more confidence that the interval had captured the parameter, what do you think would happen to the margin of error? It would be: A. smaller than 3%. B. still 3%. C. larger than 3%. D. essentially infinite, because less confidence is not possible with this small a sample. (Quiz 6)
C
A Ph.D. candidate in the College of Education once defended her misleading and confusing questionnaire by arguing that her margin of error was low, only about 3%. This argument is: A. confused, because margin of error does not apply outside of the sciences. B. correct, because 3% is very small and the parameter range is still very small. C. confused, because the margin of error has nothing to do with biased questionnaire designs. D. correct, because only about 3% of the respondents would have been affected negatively. (Quiz 11)
C
A student in a statistics class is about to start a survey sampling project. She has 113 Facebook friends and wants to distribute a questionnaire to 20 of them. Which of the following sampling plans would be the most like a real-world simple random sample? A. Post the questionnaire on Facebook and take the 20 responses you get. No reason to believe the first 20 are not just random from the larger group. B. Post the questionnaire on Facebook and wait until you get as many of the 113 responses as you can. Then select 20 of those at random. C. Select 20 names at random from the 113 Friends and contact those 20 with the questionnaire. D. Select several different samples of size 20 names from the 113 Friends. Contact each group of 20 with the questionnair and then average the reponses you get from each of those groups. (Quiz 5)
C
In the MOE Doesn't Apply Read All About It (or video), what was the issue with the question "Have you often, sometimes, hardly ever, or never felt bad because you were unfaithful to your wife?" A. Of the 15% who said they "never felt bad about it" surely most of them had really been unfaithful to their wives. But the way the question was asked there wasn't an option for them to say how. B. Of the 85% who said they "never felt bad about it" surely most of them had really been unfaithful to their wives. But the way the question was asked there wasn't an option for them to say how. C. Of the 85% who said they "never felt bad about it" surely a large part of those had never been unfaithful to their wives. But the way the question was asked this wasn't an option for an answer. D. Of the 15% who said they "never felt bad about it" surely a large part of those had never been unfaithful to their wives. But the way the question was asked this wasn't an option for an answer. (Quiz 10)
C
The University of Kentucky has 21,441 undergraduates, with a gender distribution of 49 percent male students and 51 percent female students. You take a simple random sample of 100 undergraduates (30 males and 70 females) and ask the question "Have you ever attended a date party?" 100% of the males say "yes" and 50% of the females say "yes." If the estimate of all undergraduates who would say "yes" to this question is reweighted to reflect the distribution of males and females in the U.K. population, what would that be in this case? A. About 25% B. About 85% C. About 75% D. About 65% (Quiz 7)
C
The distribution shown here represents the sampling distribution that resulted from 44 simple random samples, each of size 50, taken from a manufactured population of 250 voters. In each case the proportion of sampled voters who agreed the government was doing enough about the problem of rabid squirrels was recorded. From what you know about sampling distributions arising from simple random samples, which of the following is the most likely value of the true proportion of all 250 voters who would have agreed, had they all been asked? A. 0.19 B. Can't tell from the figure given. C. 0.27 D. 0.32 (Quiz 8)
C
The scores for all high school seniors taking the verbal section of the Scholastic Aptitude Test (SAT) in a particular year had a mean of 490 and a standard deviation of 100. The distribution of SAT scores is bell-shaped. A rather exclusive university only admits students who were among the highest 16% of the scores on this test. What minimum score would a student need on this test to be qualified for admittance to this university? A. 690 B. 490 C. 590 D. 390 (Quiz 9)
C
What does the word "parameter" refer to in statistical science? A. Number that describes the sample B. The size of the sample C. Number that describes the population D. The set of guidelines for the selecting the sample (Quiz 4)
C
What is a cross-sectional sample? A. An attempt to match the sample characteristics exactly to the type of people you prefer to interview. B. An attempt to match the population characteristics exactly to those of an already-taken sample. C. An attempt to match the sample characteristics exactly to those of the population. D. An attempt to match up pairs of people in the sample so that they look exactly like corresponding pairs in the population. (Quiz 4)
C
What is sampling variability? A. The variability seen in parameters from sample to sample B. The variability seen in statistics over time C. The variability seen in statistics from sample to sample D. The variability seen in parameters over time (Quiz 6)
C
Which of the following statements is true? A. The mean is sensitive to outliers but the standard deviation is not B. The median is sensitive to outliers but the mean is not C. The mean and standard deviation are sensitive to outliers D. The mean and median are sensitive to outliers (Quiz 3)
C
You ask a question to a random sample of 1500 adults in Texas (population 18 million people) and to a separate random sample of 500 adults in Indiana (population 5.7 million people). You make separate 95% confidence statements about the percent of all adults in each state who agree. Your margin of error for Indiana is: A. either smaller or larger than in Texas, because the sample result varies due to chance. B. smaller than in Texas, because there are fewer people in the Indiana sample. C. larger than in Texas, because there are fewer people in the Indiana sample. D. the same as in Texas, because the two samples are in the same proportion to their respective population sizes. (Quiz 8)
C
A population has 50 items, 21 green and 29 red. Turns out there are 2118760 possible samples of size 5 that can be taken from this population. If the parameter of interest is the true proportion green in the population, what is the parameter in this situation? A. 21/2118760 B. 29/2118760 C. 29/50 D. 21/50 (Quiz 5)
D
A recent poll of 1500 college-age students found that 885 agreed with U.S. foreign policy toward Israel. What is the corresponding 95% confidence interval (choose closest answer)? A. 59% plus or minus 95% B. 885 plus or minus 3% C. 885 plus or minus 95 D. 59% plus or minus 3% (Quiz 8)
D
A survey was conducted by Playboy, asking questions about the sex lives of 5,000 U.S. University and College students. One question asked: "Are you in a nude picture on someone's camera phone?" 34 percent said "yes". Name at least one error you'd expect this survey to suffer from even if all 15.9 million College and University students in the U.S. had answered, and not just 5,000. A. Error caused by camera phone restrictions on nudity B. Error caused by sampling C. Error caused by increasing confidence levels D. Error caused by fabricated responses (Quiz 11)
D
If the variance of a set of data is computed to be 4, then the standard deviation is: A. 16 B. Can't tell without having the data C. 4 over square root of n, where n is the number of data points D. 2 (Quiz 3)
D
If you want a 95% margin of error to be 1%, what will your sample size have to be? A. n = 100 B. n = 10 C. n = 1000000 D. n = 10000 (Quiz 7)
D
In BN 2.20 we found that out of 594 people asked (students, researchers), 281 reported that the right way to interpret a 95% confidence interval of 0.1 to 0.4 was to say that "the probability that the true proportion is bigger than 0 is at least 95%." What is wrong with that interpretation? A. That makes it sound like the sample proportion is random. It is not. B. That makes it sound like that 0 is in the interval 0.1 to 0.4. It is not C. That makes it sound like the confidence interval is random. It is not. D. That makes it sound like the parameter is random. It is not. (Quiz 9)
D
In BN 2.29 you studied about the role of incentives and whether they mattered. Table 2.10 (shown below) recorded the results of the Early Response incentive. What two percentages would you use to evaluate the effect of "Incentive" versus "No Incentive" on Early Response? A. 324 and 873 B. 50% and 25% C. 402 and 695 D. 16% and 32% (Quiz 11)
D
In BN 2.29 you studied about the role of incentives and whether they mattered. There were three Phases of that study. What was Phase II? A. In this Phase the 873 subjects who did not respond early (Phase I) were given an opportunity to respond in this second round. Half were offered and incentive and half were not. B. In this Phase the original 1,197 subjects were given an opportunity to respond in this second round. No incentives were offered. C. In this Phase the original 1,197 subjects were given an opportunity to respond in this second round. Half were offered an incentive and half were not. D. In this Phase the 873 subjects who did not respond early (Phase I) were given an opportunity to respond in this second round. No incentives were offered. (Quiz 11)
D
Recall the sampling distribution of the sample proportion (page 162 in your book). Specify an interval (range) in which 68% of all sample proportions based on samples of size n could be expected to occur. A. Within (1/sqrt(n)) on either side of the parameter p. B. Within (0.5)x(1/sqrt(n)) on either side of the sample proportion phat. C. Within (1/sqrt(n)) on either side of the sample proportion phat. D. Within (0.5)x(1/sqrt(n)) on either side of the parameter p. (Quiz 8)
D
Recently the Central Kentucky Youth Orchestras started posting rehearsal participation as percentages. So if there are 10 trumpets in an orchestra and 9 showed up to rehearsal, then they'd report a 90% participation rate for trumpets. For sake of simplicity, suppose unbeknownst to the public there are 4 flutes and 10 trumpets. Suppose one flute misses rehearsal and one trumpet misses rehearsal. Would reporting participation results as percentages for each group be potentially misleading? Why or why not? A. No. A 75% rate for flutes and 90% rate for trumpets fairly summarizes that there are more non-compliant flutists than trumpeters. B. No. In each case only one person missed and the participation rates would therefore be the same for flutes and trumpets, making them look equally compliant. C. Yes. In each case only one person missed but the participation rates would be 90% for flutes and 75% for trumpets, making trumpets look less compliant. D. Yes. In each case only one person missed but the participation rates would be 75% for flutes and 90% for trumpets, making trumpets look more compliant. (Quiz 2)
D
Refer to the graphic below. We encountered this summary of the sampling distribution of the sample proportion in class. Suppose n = 100. What are the chances of an SRS of this size yielding a phat that is somewhere between p - 0.1 and p + 0.1? A. 68 out of 100 B. 99.7 out of 100 C. 13.5 out of 100 D. 95 out of 100 (Quiz 9)
D
Robert Niles is a former mathematics geek turned journalist who is continually trying to educate other journalists about how to interpret statistical arguments. He recently noted "Don't overlook that fact that the margin of error is a 95 percent confidence interval, either. That means that for every 20 times you repeat this poll, statistics say that one time you'll get an answer that is completely off the wall." What does Niles mean by this statement? A. That the "confidence" is in a repeated sampling sense but in reality it is very difficult to actually repeat a sample without human error more than 1 time in 20. B. That the "confidence" is in a repeated sampling sense; and to say one gets an interval that is "right" 95% of the time, is to say one will get a "wrong" one 20% of the time. C. That the "confidence" is in a repeated sampling sense but in reality it is very difficult to actually repeat a sample without human error more than 20 times in a hundred. D. That the "confidence" is in a repeated sampling sense; and to say one gets an interval that is "right" 95% of the time, is to say one will get a "wrong" one 5% of the time. (Quiz 7)
D
Suppose we measured all of your wingspans in class. What would happen to that average wingspan if we added ex-UK player and NBA star Anthony Davis' to the data? A. It would decrease B. It would stay the same since we'd have just one more wingspan and the average would be in the middle C. It would necessarily be greater than the standard deviation of the same data D. It would increase (Quiz 3)
D
What kind of error does the margin of error address? A. Fabrication errors B. Non-sampling error C. Non-mathematical error D. Random sampling error (Quiz 10)
D
Which of the following sources of error is addressed by the margin of error? A. Errors in entering the data into the computer B. Errors because subjects weren't truthful C. Errors because some of the subjects did not understand the questions D. Errors that come from choosing a sample and not the entire population (Quiz 11)
D