a

In Exercises 9–12, determine whether the sampling method appears to be sound or is flawed.

Nuclear Power Plants In a survey of 1368 subjects, the following question was posted on the USA Today website: “In your view, are nuclear plants safe?” The survey subjects were Internet users who chose to respond to the question posted on the electronic edition of USA Today.

In Exercises 9–12, determine whether the sampling method appears to be sound or is flawed.

Clinical Trials Researchers at Yale University conduct a wide variety of clinical trials by using subjects who volunteer after reading advertisements soliciting paid volunteers.

In Exercises 13–20, determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance.

Mendel’s Genetics Experiments One of Gregor Mendel’s famous hybridization experiments with peas yielded 580 offspring with 152 of those peas (or 26%) having yellow pods. According to Mendel’s theory, 25% of the offspring peas should have yellow pods.

In Exercises 13–20, determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance.

Election Fraud The County Clerk in Essex County, New Jersey, was responsible for randomly assigning the order in which candidates’ names appeared on a recent election ballot. Among 41 different ballots, a Democrat was placed on the first line 40 times, and a Republican was placed on the first line once.

In Exercises 25–28, refer to the data in the table below. The entries are for five different years, and they consist of weights (metric tons) of lemons imported from Mexico and U.S. car crash fatality rates per 100,000 population [based on data from “The Trouble with QSAR (or How I Learned to Stop Worrying and Embrace Fallacy)” by Stephen Johnson, Journal of Chemical Information and Modeling, Vol. 48, No. 1].

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Conclusion If we were to use the sample data and conclude that there is a correlation or association between lemon imports and crash fatality rates, does it follow that lemon imports are the cause of fatal crashes?

In Exercises 29–36, identify what is wrong.

Potatoes In a poll sponsored by the Idaho Potato Commission, 1000 adults were asked to select their favorite vegetables, and the favorite choice was potatoes, which were selected by 26% of the respondents.

In Exercises 29–36, identify what is wrong.

Healthy Water In a USA Today online poll, 951 Internet users chose to respond, and 57% of them said that they prefer drinking bottled water instead of tap water.

In Exercises 29–36, identify what is wrong.

Cell Phones and Pirates In recent years, the numbers of cell phones and the numbers of pirates have both increased, so there is a correlation, or association, between those two variables. Therefore, pirates cause increases in cell phones.

In Exercises 29–36, identify what is wrong.

Storks and Babies In the years following the end of World War II, it was found that there was a strong correlation, or association, between the number of human births and the stork population. It therefore follows that storks cause babies.

In Exercises 37–44, answer the given questions, which are related to percentages.

Workplace Attire In a survey conducted by Opinion Research Corporation, 1000 adults were asked to identify “what is inappropriate in the workplace.” Of the 1000 subjects, 70% said that miniskirts were not appropriate in the workplace.

b. Among the 1000 respondents, 550 said that shorts are unacceptable in the workplace. What percentage of respondents said that shorts are unacceptable in the workplace?

In Exercises 37–44, answer the given questions, which are related to percentages.

Checking Job Applicants In a study conducted by the Society for Human Resource Management, 347 human resource professionals were surveyed. Of those surveyed, 73% said that their companies conduct criminal background checks on all job applicants.

a. What is the exact value that is 73% of the 347 survey subjects?

b. Could the result from part (a) be the actual number of survey subjects who said that their companies conduct criminal background checks on all job applicants? Why or why not?

In Exercises 37–44, answer the given questions, which are related to percentages.

Marriage Proposals In a survey conducted by TheKnot.com, 1165 engaged or married women were asked about the importance of a bended knee when making a marriage proposal. Among the 1165 respondents, 48% said that the bended knee was essential.

a. What is the exact value that is 48% of 1165 survey respondents?

b. Could the result from part (a) be the actual number of survey subjects who said that a bended knee is essential? Why or why not?

In Exercises 37–44, answer the given questions, which are related to percentages.

Texting While Driving USA Today reported results from an Arity survey in which 2018 drivers were asked if they text while driving.

a. Among the respondents, 42% said that they text while driving. What is the exact value that is 42% of the number of respondents?

b. Could the result from part (a) be the actual number of respondents who said that they text while driving? Why or why not?

In Exercises 37–44, answer the given questions, which are related to percentages.

Percentages in Advertising An ad for Big Skinny wallets included the statement that one of their wallets “reduces your filled wallet size by 50%–200%.” What is wrong with this statement?

In Exercises 37–44, answer the given questions, which are related to percentages.

Percentages in Advertising In an actual ad for the Club, a device used to discourage car thefts, it was stated that “The Club reduces your odds of car theft by 400%.” What is wrong with this statement?

In Exercises 21–28, determine which of the four levels of measurement (nominal, ordinal, interval, ratio) best describes the given data.

College Students In order to better plan for the incoming freshman class, a college dean asks each newly admitted student to identify their likely major (physics, business, math, psychology, engineering, law, etc.).

Quantitative/Categorical Data Identify each of the following as quantitative data or categorical data.

a. The platelet counts in Data Set 1 “Body Data” in Appendix B

Quantitative/Categorical Data Identify each of the following as quantitative data or categorical data

c. The colors of the M&M candies in Data Set 38 “Candies” in Appendix B

Discrete/Continuous Data Which of the following describe discrete data?

a. The exact heights of all NBA basketball players

Parameter and Statistic In a Citrix Security survey of 1001 adults in the United States, it was found that 69% of those surveyed believe that having their personal information stolen is inevitable. Identify the population and sample. Is the value of 69% a statistic or a parameter?

E-Cigarette Survey In a survey of 36,000 adults, 3.7% said that they regularly use E-cigarettes (based on data from the National Center for Health Statistics)

c. What is the level of measurement of the value of 3.7%? (nominal, ordinal, interval, ratio)

In Exercises 5–12, identify whether the given value is a statistic or a parameter.

Drivers According to the Federal Highway Administration, there are 212 million licensed drivers in the United States.

In Exercises 5–12, identify whether the given value is a statistic or a parameter.

Smart Phones In a Pew Research Center poll, a sample of adults in the United States was obtained, and it was found that 72% of them own smart phones.

In Exercises 13–20, determine whether the data are from a discrete or continuous data set.

Fraud Detection While monitoring Internet traffic in order to detect fraudulent activity, a researcher records the interarrival times (sec) between incoming Internet queries.

In Exercises 13–20, determine whether the data are from a discrete or continuous data set.

Students Your statistics professor records the number of students who pass each of her courses.

In Exercises 13–20, determine whether the data are from a discrete or continuous data set.

Statistics Classes In each of her classes, a statistics professor records the number of students who earned a grade of A.

In Exercises 21–28, determine which of the four levels of measurement (nominal, ordinal, interval, ratio) best describes the given data.

Movie Ratings In a college film studies course, students rate ten documentaries using a scale of 0 to 5 stars.

In Exercises 21–28, determine which of the four levels of measurement (nominal, ordinal, interval, ratio) best describes the given data.

Criminology In a criminology study, the lengths of prison sentences are obtained for randomly selected subjects convicted of auto theft.

In Exercises 21–28, determine which of the four levels of measurement (nominal, ordinal, interval, ratio) best describes the given data.

Areas of States A data set consists of the areas of each of the 50 United States.