Braking reaction times of 36 randomly selected licensed drivers are measured. Are those data considered quantitative or qualitative? If quantitative, are those values continuous or discrete?
> What percentage of adult males have pulse rates less than 81 bpm?
> What percentage of adult males have pulse rates greater than 53 bpm?
> In 1965, Intel cofounder Gordon Moore initiated what has since become known as Moore’s law: The number of transistors per square inch on integrated circuits will double approximately every 18 months. In the table below, the first and th
> What is the standard score (z-score) corresponding to the pulse rate of 53 bpm for an adult male?
> Samples of 36 adult males are randomly selected and the mean is found for each sample. What is the standard deviation of the sample means?
> Samples of 36 adult males are randomly selected and the mean is found for each sample. What is the mean of the sample means?
> Use Table A-1 to find the percentage of pulse rates of adult men between 60 and 80 bpm.
> Using the 68-95-99.7 rule, find the percentage of pulse rates of adult men between 48 and 92 bpm.
> Periodically, some researchers test the hypothesis that cell phones can cause a cancer in those who use them. In one such study, it was found that among 420,095 cell phone users, 135 developed cancer of the brain or nervous system.
> Which of the following is likely to have a distribution that is closest to a normal distribution? a. The outcomes that occur when a single die is rolled many times b. The outcomes that occur when two dice are rolled many times and the mean is computed ea
> What percentage of adult males have pulse rates between 59 and 92 bpm?
> Which of the following statements are correct? a. A normal distribution is any distribution that typically occurs. b. The graph of a normal distribution is bell-shaped. c. The graph of a normal distribution always has one mode. d. In a normal distributio
> Which of the following statistics would be best for monitoring the consistency of the weights of Dunkin’ Donuts regular doughnuts: mean, median, mode, range, standard deviation?
> The pie charts in Figure 3.38 give the percentages of Americans in three age categories in 1990 and 2050 (projected). a. Consider the 1990 age distribution. The actual percentages for the three categories for 1990 were 87.5% (others), 11.3% (60â
> Which of the following statements could apply to a data set consisting of 1000 values that are all deferent? a. The 20th percentile is greater than the 30th percentile. b. The median is greater than the first quartile. c. The third quartile is greater th
> A histogram is constructed for a large set of pulse rates of adult males, and it is found that the distribution is symmetric and unimodal. What does this imply about the values of the mean and median?
> Find the standard deviation of these earthquake magnitudes: 2.99, 2.58, 2.44, 2.91, and 3.38.
> Use the range rule of thumb to estimate the standard deviation of the earthquake magnitudes given in Exercise 1. How close is the result to the actual standard deviation of 0.999?
> The standard deviation of the magnitudes given in Exercise 1 is 0.999. What characteristic does that value measure?
> What is the range of the magnitudes given in Exercise 1?
> Nine-year-old Emily Rosa became an author of an article in the Journal of the American Medical Association after she tested professional touch therapists (see “Focus on Education” in Chapter 10). Using a cardboard partition, she held her hand above the t
> Find the median of the magnitudes given in Exercise 1.
> Identify the names of the components that constitute the five number Summary for a data set.
> When you add the earthquake magnitudes 2.45, 3.62, 3.06, 3.30, and 1.09, then divide by the number of values, the result is 2.704. Which term best describes this value: average, mean, median, mode, or standard deviation?
> Refer to Figure 3.37 in Exercise 15 and construct a bar chart to depict the same data in a way that is fair and objective. Figure 3.37
> When constructing a graph of the same categorical data, why is a Pareto chart generally better than a pie chart?
> In 1986, the subway fare in New York City was $1, and the fare in 2015 was $2.50. In Figure 3.45, the bill representing the 2015 fare is 2.5 times as tall and 2.5 times as wide as the bill representing the 1986 fare. Does the graphic convey the actual ch
> The third category in a frequency table has a cumulative frequency of 95. What does the value of 95 indicate?
> The first category in a relative frequency table is 90–100, and the corresponding relative frequency is 0.18. What does the value of 0.18 indicate?
> The first category in a frequency table is 90–100, and the corresponding frequency is 76. What does the value of 76 indicate?
> A dot plot of braking distances (in feet) of cars is constructed, and a portion of the dot plot is shown below. Identify the values represented in this dot plot. Figure 3.44
> A stem plot is created with the braking distances (in feet) of cars, and one row of that stem plot is 14 | 000335. Identify the values represented by that row.
> In a study of the effects of magnets on back pain, some subjects were treated with magnets while others were given non-magnetic devices with a similar appearance. The magnets did not appear to be effective in treating back pain (Journal of the American M
> As a quality control manager at Ford, you monitor the time it takes to manufacture each new Taurus car. Which of the following graphs would be best for displaying those times: histogram, bar graph, Pareto chart, dot plot, or pie chart?
> Why are pictographs generally poor for depicting one- dimensional data, such as consumption of oranges in different years?
> Figure 3.37 depicts the amounts of daily oil consumption (in millions of barrels) in the United States and Japan. Does the illustration accurately depict the data? Why or why not? Figure 3.37
> Listed below are body temperatures (in °F) of healthy adults. Why would a graph of these data not be very effective in helping us understand them? 98.6 98.6 98.0 98.0 99.0 98.4 98.4 98.4 98.4 98.6 Answer: The data set is too small for a graph to revea
> As a quality control manager at Ford Motor Company, you find that repairs needed on new cars have various causes, including software, human error, and worn machinery. Which graph would be most appropriate for these data: histogram, bar graph, Pareto char
> The Telektronics Company has been in business for five years, and the following table lists the company’s net profit in each of those years. Using the first year as a reference value, find the index number for the net profit in the seco
> Two different students measure the height of an instructor who is actually 178.44 cm tall. The first student obtains a measurement of 178 cm and the second student obtains a measurement of 179.18 cm. Which measurement is more accurate? Which measurement
> In a Gallup poll of 1038 adults, 5% of the respondents said that second-hand smoke is not at all harmful. How many respondents said that second-hand smoke is not at all harmful?
> Recorded survey results include the states in which respondents reside. Are those data considered quantitative or qualitative, and what is their level of measurement (nominal, ordinal, interval, or ratio)?
> Braking reaction times of 36 randomly selected licensed drivers are measured and 20 of them are greater than 1.9 seconds. What is the percentage of reaction times greater than 1.9 seconds?
> A researcher measures the braking reaction time of a subject and records a value of 2.4 seconds, but the subject’s actual braking reaction time is 1.9 seconds. What is the relative error?
> Tempered glass is used for car windows because it is much tougher than regular glass. A researcher tests the strength of samples of glass by heating them at 620°C, which is the industry standard.
> A researcher measures the braking reaction time of a subject and records a value of 2.4 seconds, but the subject’s actual braking reaction time is 1.9 seconds. What is the absolute error?
> You want to conduct a survey of parents of elementary school students in Minneapolis by using telephone calls instead of personal visits. Assume you have directories listing telephone numbers of all (or almost all) parents at each of the city’s elementar
> What is the level of measurement of the values described in Exercise 1 (nominal, ordinal, interval, or ratio)?
> Refer to the table in Exercise 9. If the net profit in the sixth year is projected to be 5% less than the net profit in the fifth year, what is that projected sixth-year net profit?
> If a statistical study is carefully conducted in every possible way, then: (a) Its results must be correct; (b) We can have confidence in its results, but it is still possible that the results are not correct; (c) We say that the study is perfectly biase
> Consider a survey of randomly selected people in which it is found that participants who used sunscreen were more likely to have been sunburned in the past year. Which explanation for this result seems most likely? (a) Sunscreen is useless; (b) The peop
> Consider a study in which you measure the weights of dolphins. The variable of interest in this study is: (a) The size of the sample; (b) The weights of dolphins; (c) The average (mean) weight of all dolphins.
> From the poll results given in Exercise 11, can we safely conclude that the majority of people are most annoyed by the use of “whatever” in conversation?
> In a Marist Poll, respondents chose the most annoying phrases used in conversation. Among the 864 subjects who were surveyed, 51% chose “whatever.” The survey has a margin of error of 3 percentage points. Identify the range of values for the confidence i
> If all subjects in the aspirin treatment group are athletes and all subjects in the control group are not athletes, then there is a danger of which of the following: (a) Samples those are too small; (b) Confounding; (c) Blinding.
> The Nielsen Company installs devices in homes to record the TV shows that are watched. The results are then used to provide ratings identifying which shows are being viewed more than others.
> Figure 3.36 on the next page depicts the annual high values of the Dow Jones Industrial Average (DJIA) for stocks. How is this graph misleading? How could it be drawn so that it is not misleading? In this case, would the graph change dramatically if it w
> In a Gallup poll of 1018 adults, it was found that 22% smoked cigarettes in the past week.
> If we see a placebo effect, it means: (a) The experiment was not really double-blind; (b) The experimental groups were too small; (c) Pulse rates were lowered among some of those in the placebo group.
> The purpose of the placebo is: (a) To prevent participants from knowing whether they belong to the treatment group or the control group; (b) To distinguish between the cases and the controls in a case-control study; (c) To determine whether pulse rates a
> The subjects do not know whether they are given aspirin or a placebo, and the evaluators who measure the pulse rates also do not know. This trial is: (a) Single-blind; (b) Double-blind; (c) Not blinded.
> Is this an experiment or an observational study?
> Are the survey results a sample or a census?
> If we learn that the sample is representative of the population, which of the following best describes the results: (a) The results found for the sample are similar to those we would find for the entire population; (b) The sample is very large; (c) The
> What do we mean by critical values for significance in a hypothesis test for the population proportion? How does this compare to the critical values for statistical significance for a population mean? How do we use this for making decisions about the hyp
> When testing a claim about a population proportion, what is a standard score, z, for the sample proportion, pˆ?
> What do n, p, pˆ , and P-value represent?
> Figure 3.35 shows the median home prices in regions of the United States. How is the graph misleading? How could it be drawn so that it is not misleading? Figure 3.35
> The Genetics and IVF Institute conducted a clinical trial of the YSORT method designed to increase the probability of conceiving a boy. As of this writing, 291 babies were born to parents using the YSORT method, and 82% of them were boys. Test the claim
> The Department of Transportation used a retrospective study to determine that air bags save lives.
> The Genetics and IVF Institute conducted a clinical trial of the XSORT method designed to increase the probability of conceiving a girl. As of this writing, 945 babies were born to parents using the XSORT method, and 93% of them were girls. Test the clai
> In clinical tests of the drug Lipitor, 863 patients were treated with the drug and 19 of them experienced flu symptoms (based on data from Parke-Davis). Test the claim that the percentage of treated patients with flu symptoms is greater than the 1.9% rat
> According to the Energy Information Administration, 53.0% of U.S. households used natural gas for heating in 1997. A recent survey of 3600 randomly selected U.S. households showed that 54.0% used natural gas. Use a 0.05 significance level to test the cla
> When 3011 adults were surveyed in a Pew Research Center poll, 2198 said that they use the Internet. Is it accurate for a newspaper reporter to write that “3/4 of all adults use the Internet”? Why or why not?
> In a study of 1228 randomly selected medical malpractice lawsuits, it was found that 856 of them were dropped or dismissed (based on data from the Physicians Insurers Association of America). Test the claim that most medical malpractice lawsuits are drop
> In a KRC Research poll, 1002 adults were asked if they felt vulnerable to identity theft, and 53% of them said “yes.” Test the claim that the majority of adults feel vulnerable to identity theft.
> A Department of Health and Human Services study of illegal drug use among 12- to 17-year-olds reported a decrease in use (from 11.4% in 1997) to a current level of 9.9%. Suppose a survey in a large high school reveals that, in a random sample of 1050 stu
> Based on information from the National Cyber Security Alliance, 93% of computer owners believe that they have antivirus programs installed on their computers. In a random sample of 400 scanned computers, it is found that 380 of them (or 95%) actually hav
> To show how sugar production doubled from 1990 to now, an illustrator draws two sugar cubes. The first cube is drawn with a length of 1 cm on each side, and the second cube is drawn with a length of 2 cm on each side. What are the volumes of the two suga
> Listed below are the lengths (in minutes) of animated children’s movies. Construct a stem plot. Does the stem plot show the distribution of the data? If so, how? 83 88 120 64 69 71 76 74 75 76 75 75 79 80 78 78 83 77 71 83 80 73 72 82 74 84 90 89 81 81 9
> A study commissioned by the U.S. Department of Education, based on responses from 1015 randomly selected teenagers, concluded that 44% of teenagers cite grades as their greatest source of pressure. Test the claim that fewer than half of all teenagers in
> A survey showed that among 785 randomly selected subjects who completed four years of college, 144 smoke and the others do not smoke (based on data from the American Medical Association). Test the claim that the rate of smoking among those with four year
> A psychologist suspects that breathing exercises can help people with depression. To decide whether he is correct, he identifies a group of subjects, watches them do the breathing exercises, and then asks them how they feel afterward.
> In a 3M Privacy Filters poll, 806 adults were asked to identify their favorite seat when they fly, and 61% of them chose a window seat. Test the claim that the majority of adults prefer window seats when they fly.
> The claim p > 0.5 can never be supported if the sample proportion p̂ is less than 0.5.
> The area to the right of the standard score z = 1.0 is 0.1587, so the P-value in a two-tailed test is 0.1587.
> In a hypothesis test involving a claim made about a population proportion, if there is sufficient evidence to reject the null hypothesis, then there may or may not be sufficient evidence to support the alternative hypothesis.
> In a test of the claim that a majority of Americans believe that human activity is the major cause of global warming, the null hypothesis is p = 0.5 and the alternative hypothesis is p > 0.5.
> A survey of 61,647 people included several questions about office relationships. Of the respondents, 26% reported that bosses scream at employees. The survey was an Elle/MSNBC.com survey to which Internet users chose whether to respond. It is valid to us
> A P-value of 0.00001 is obtained when sample data are used to test the claim that the majority of car crashes occur within 5 miles of home. What does this P-value tell us?
> A newspaper used images of cigarettes of different sizes to depict the percentages of adults who smoke in 2000 and in 2017. Which graphic would depict these data more objectively: a bar graph or images of two cigarettes of different sizes? Why?
> In hypothesis tests, if the significance level is 0.01, then the P-value is also 0.01.
> What is a type I error? What is a type II error?
> What do we mean by critical values for significance in a hypothesis test for the population mean? How do we use critical values for making decisions about hypothesis tests?
> Consumer Reports rated house paints according to how well they hold up to hot weather by conducting an experiment in which they applied the various paints to identical surfaces that were then left exposed to the same hot weather conditions for the same l
> When testing a claim about a population mean, what is a standard score for the sample mean?
> Briefly describe what each of the variables n, x‾, s, σ , and μ represent in hypothesis tests of a claim made about a population mean.
> H0: The mean length of a bolt in the suspension system of new Audi cars is 3.456 centimeters. Ha: The mean length of a bolt in the suspension system of new Audi cars is not equal to 3.456 centimeters.
> H0: The lottery is fair. Ha: The lottery is biased.
> H0: The defendant is not guilty. Ha: The defendant is guilty.
