Statistics Ch 1 Answers

ch01 Student: 1. A knowledge of statistics provides the necessary tools to differentiate between sound and questionable conclusions. True False 2. Statistics is the methodology of extracting unnecessary information from a data set. True False 3. The branch of statistical studies called descriptive statistics summarizes important aspects of a data set. True False 4. The branch of statistical studies called inferential statistics refers to drawing conclusions about sample data by analyzing the corresponding population. True False 5. A population is a larger data set than its corresponding sample. True False 6. Population parameters are used to estimate corresponding sample statistics. True False 7. Typically, it is possible to examine every member of the population. True False 8. Cross-sectional data contain values of a characteristic of one subject collected over time. True False 9. Time series data contains values of a characteristic of a subject over time. True False 10. Sampling is often necessary due to the potential cost and time of gathering population data. True False 11. Sampling allows researchers to draw conclusions about the population. True False 12. A qualitative variable assumes meaningful numerical values. True False 13. Both discrete and continuous variables may assume an uncountable number of values. True False 14. A discrete variable cannot assume an infinite number of values. True False 15. A continuous variable assumes any value from an interval (or collection of intervals). True False 16. A professor's gender (male, female) as well as rank (assistant, associate, full) represent ordinal data. True False 17. A professor's rank (assistant, associate, and full), as well as salary, represent ordinal data. True False 18. The study of statistics can be defined as A. The language of data. B. The art and science of getting information from data. C. The study on collecting, analyzing, presenting, and interpreting data. D. All of the above. 19. When reading published statistics (numerical facts), you should . A. Never believe what you read, since all statistics are lies B. Only believe those statistics that are adequately supported C. Believe what you read, since they wouldn't be published if they weren't correct D. Only believe those statistics that are presented in so-called quality publications 20. The two branches of the study of statistics are generally referred to as A. Descriptive and inferential statistics B. Inferential and differential statistics C. Descriptive and referential statistics D. Differential and descriptive statistics . 21. Population parameters are difficult to calculate due to . A. Cost prohibitions on data collection B. The infeasibility of collecting data on the entire population C. The fact that samples are difficult to draw due to the nature of the data D. A and B 22. The teachers union in California wants to know the average salary for high school teachers throughout the country. What will the teachers union presumably calculate? A. Sample statistic B. Sample parameter C. Population statistic D. Population parameter 23. A population consists of . A. All items of interest in a sample B. A subject of interest in a sample C. All items of interest in a statistical problem D. A subject of interest in a statistical problem 24. In inferential statistics, we calculate statistics of sample data to A. Estimate unknown population parameters B. Conduct tests about unknown population parameters C. A and B D. None of the above . 25. Which of the following represents a population and a sample from that population? A. Residents of Albany, New York, and registered voters in Albany, New York B. Teachers in a high school and members of the parent teacher group C. Fans at a concert who purchase t-shirts, and fans at a concert who purchase soda D. Freshmen at St. Joseph's University and basketball players at St. Joseph's University 26. Which of the following is an example of cross-sectional data? A. GDP of the United States from 1990-2010 B. Daily price of DuPont stock during the first quarter C. Quarterly housing starts collected over the last 60 years D. Results of market research testing consumer preferences for soda 27. Which of the following is an example of time series data? A. The sales price of townhouses sold last year B. Quarterly housing starts collected over the last 60 years C. Results of market research testing consumer preferences for soda D. Starting salaries of recent business graduates at Penn State University 28. The estimation of which of the following requires sampling? A. U.S. unemployment rate B. Total rainfall in Phoenix, Arizona in 2010 C. The Cleveland Indians' hitting percentage in 2010 D. The average SAT score of incoming freshmen at a university 29. A company wants to estimate the mean price of oil over the past 10 years. What kind of data does the company need? A. Time series data B. Inferential statistics C. Cross-sectional data D. Descriptive statistics 30. For which of the following population parameters is sampling not necessary? A. The average height of NBA players B. The average life of light bulbs produced by a manufacturer C. The average content of cereal boxes produced by a manufacturer D. The percentage of the U.S. public school teachers who support Democrats 31. Sampling is used heavily in manufacturing and service settings to ensure high-quality products. In which of the following areas would sampling be inappropriate? A. Computer assembly B. Custom cabinet making C. Cell phone manufacturing D. Technical support by phone 32. Which of the following are examples of cross-sectional data? A. The test scores of students in a class B. The current average prices of regular gasoline in different states C. The sales prices of single-family homes sold last month in California D. All of the above 33. An analyst studies a data set of the 2011 year-end book value per share for all companies listed on the New York Stock Exchange. This data set is best described as . A. Time-series data B. Cross-sectional data C. Neither time-series nor cross-sectional data D. A combination of time-series and cross-sectional data 34. Which type of data, cross-sectional versus time series, is more important to research? A. Neither type of data is important. B. Cross-sectional data is more important than time series data. C. Time series data is more important than cross-sectional data. D. Time series data and cross-sectional data are equally as valuable in different types of research. 35. Which of the following variables is qualitative? A. Height B. Gender C. Weight D. Temperature 36. Which of the following variables is quantitative? A. Gender B. Temperature C. Marital status D. Religious affiliation 37. Which of the following is a quantitative variable? A. House age B. House size C. House price D. All of the above 38. San Francisco 49ers linebacker Patrick Willis won the Defensive Rookie of the Year Award in 2007 with a total of 174 tackles. Tackles are measured on what kind of a scale? Is a variable measuring the number of tackles considered continuous or discrete? A. Ratio scale; discrete B. Interval scale; discrete C. Ratio scale; continuous D. Interval scale; continuous 39. Which of the following variables is not continuous? A. Height of NBA players B. Time of a flight between Atlanta and Chicago C. Average temperature in the month of July in Orlando D. The number of obtained heads when a fair coin is tossed 20 times 40. The ordinal scale of data measurement is A. Less sophisticated than the nominal scale B. More sophisticated than the interval scale C. More sophisticated than the nominal scale D. As equally sophisticated as the nominal scale . 41. The interval scale of data measurement is . A. Less sophisticated than the ratio scale B. More sophisticated than the ratio scale C. Less sophisticated than the ordinal scale D. Equally sophisticated as the ratio scale because both are appropriate for quantitative data 42. A recent survey of 200 small firms (annual revenue less than $10 million) asked whether an increase in the minimum wage would cause the firm to decrease capital spending. Possible responses to the survey question were: "Yes," "No," or "Don't Know." This data is best classified as . A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 43. Which scale of data measurement is appropriate for the names of companies listed on the Dow Jones Industrial Average? A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 44. An analyst collects data on the weekly closing price of gold throughout a year. The scale of this data is . A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 45. An undergraduate student's status (freshman, sophomore, junior, and senior) is an example of which scale of measurement? A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 46. The Fahrenheit scale for measuring temperature would be classified as A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale . 47. At the end of a semester college students evaluate their instructors by assigning them to one of the following categories: Excellent, Good, Average, Below Average, and Poor. The measurement scale is . A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 48. What is the scale of measurement of the distance between any two locations? A. Ratio scale B. Ordinal scale C. Interval scale D. Nominal scale 49. Which scales of data measurement are associated with quantitative data? A. Interval and ratio B. Ratio and nominal C. Ordinal and interval D. Nominal and ordinal 50. Which data scales of measurement are associated with qualitative data? A. Interval and ratio B. Ratio and nominal C. Ordinal and interval D. Nominal and ordinal 51. Philadelphia experienced a record amount of rainfall in August of 2011. During the last week of the month, they received additional rain from a hurricane. Since global warming is thought to cause extreme weather patterns, one conclusion that could be drawn is that these patterns are evidence of global warming. What is wrong with this conclusion? 52. Administrators have concluded that the SAT exam results for 2011 show a distinct change in student capabilities when compared with the year 1991. In 1991 the SAT exam included only multiple choice sections, and was later redesigned. What is wrong with this conclusion? 53. A university is interested in tracking the success of its graduates by measuring the length of each graduate's job search before getting a position in his or her chosen field. How would you define the appropriate population? 54. We would like to determine whether there is a difference between the height of a college team of basketball players at the Ohio State University and the overall student body. Identify the two populations in this study. 55. In each of the following statements, determine whether the branch of statistics is best classified as descriptive statistics or inferential statistics. A. The average of a data set is equal to 35.7. B. The minimum value of a data set is 78, and the maximum value is 146. C. Since the average age in a sample is 23, it is likely that the average age in the population is about 23. D. Since the values in the sample are so widely dispersed, the spread of the population must be high. 56. A car company wants to know the average age of cars of their brand that are still on the road. How would you define the appropriate population? Will the car company calculate a population parameter or sample statistic? Why? 57. What are the primary reasons why sampling is necessary? 58. An investor wants to know today's average closing price of the stocks listed on the Standard and Poor's 500 Index. Will the investor calculate a population parameter or sample statistic? Why? 59. We would like to determine the average height of a college team of basketball players at Ohio State University. Is it necessary to take a sample of basketball players? Explain. 60. We would like to determine the average height of the overall student body at Ohio State University. Does it seem necessary to take a sample from the overall student body? 61. Researchers are interested in completing a study examining trends in the sale of foods in the U.S. They have decided to examine the quantity of organic vegetables sold by supermarkets. Will researchers be able to gather population data? 62. Every 10 years, a census is taken in the U.S. by the Census Bureau. Despite the intent of gathering data on the population of the United States, issues exist which make true population data impossible to gather. Identify at least two issues in collecting these data. 63. Social networking sites support themselves in large part by selling advertising space. The hit rate on these ads is a critical measure when trying to solicit advertising. The hit rate is used as a measure of success for ads. How would you recommend a social networking site go about sampling to evaluate its existing ads? 64. The following table includes the number of white women over the age of 20 in the civilian labor force. Since it is time series data, what would the entries of the first column refer to? 65. A study of teen smoking is planned. Researchers are interested in collecting cross-sectional data, which allow them to draw conclusions about the likelihood, frequency, and longevity of teen smoking. You have been asked to design this study, and will collect no more than 5 pieces of data. What information will you collect? 66. Define the measurement scale of a car's fuel efficiency (measured in miles per gallon). Is a car's fuel efficiency discrete or continuous? 67. A study of teen smoking is planned. Researchers are interested in collecting data which allow them to draw conclusions about the likelihood, frequency, and longevity of teen smoking. The questions asked include: "What is your gender?", "What is your age?", "Do you smoke (yes or no)?", "How many cigarettes per day do you smoke?", "For how long have you smoked (in years)?" What is the measurement scale for each variable? 68. The following data represent a sample of property sales in Cape May County during the year 2000. Identify the qualitative and quantitative variables. What are the natural categories for Town and Class? Identify the measurement scales for all variables. 69. The following data represent a sample of non-elementary mathematics teachers in Bergen County, New Jersey. Identify the qualitative and quantitative variables, the categories associated with each qualitative variable, and the measurement scales for all variables. 70. The following data concern a sample of employees of the U.S. Marshalls in the state of New York. Identify the qualitative and quantitative variables, the categories associated with each qualitative variable, and the measurement scales for all variables. 1. TRUE 2. FALSE 3. TRUE 4. FALSE 5. TRUE 6. FALSE 7. FALSE 8. FALSE 9. TRUE 10. TRUE 11. TRUE 12. FALSE 13. FALSE 14. FALSE 15. TRUE 16. FALSE 17. FALSE 18. D 19. B 20. A 21. D 22. A 23. C 24. C 25. A 26. D 27. B 28. A 29. A 30. A 31. B 32. D 33. B 34. D 35. B 36. B ch01 Key 37. D 38. A 39. D 40. C 41. A 42. D 43. D 44. A 45. B 46. C 47. B 48. A 49. A 50. D 51. The existence or nonexistence of climate change cannot be based on one month's worth of data. We must instead look at long-term trends. 52. The redesign of the exam makes any conclusions comparing 1991 to 2011 invalid. 53. The population should include all graduates of the university within a specified time period. 54. Varsity basketball players at OSU, all students at OSU Feedback: Descriptive statistics refers to the summary of a data set, and inferential statistics refers to drawing conclusions about a population based on a sample. 55. Descriptive Statistics: A, B; Inferential Statistics: C and D 56. The population includes all cars of their brand still on the road. The car company will calculate a sample statistic. It would be very costly to find the age of every car of their brand on the road. 57. Gathering population data can be sometimes impossible, very time-consuming, or very expensive. 58. The investor will calculate a population parameter. It is easy to gather all the prices for the firms on the Standard and Poor's 500 Index. 59. No, it is a small population and it is very easy to get the heights of the entire basketball team. 60. Yes, it would be very difficult and expensive to collect the heights of so many students. 61. No, population data would be very impractical and expensive to gather. 62. Homeless population not surveyed, people providing intentionally false responses, illegal immigrants not wanting to be counted, no enforcement on returning completed survey, new homes being missed or demolished homes being counted, etc. 63. The existing ads should be split into categories of like products. Then some number of ads from each category could be selected for the sample to determine the average number of hits for the relevant category. Any other logical sampling methods are acceptable. 64. Time measured in years, quarters, months, etc. 65. "What is your gender?", "What is your age?", "Do you smoke?", "How many cigarettes per day do you smoke?", "For how long have you smoked?" (Other reasonable answers are acceptable.) 66. Fuel efficiency is measured on a ratio scale. The number zero is meaningful. Fuel efficiency is a continuous variable. Feedback: If we are presented with nominal data, all we can do is categorize or group the data. The values in the data set differ merely by name or label. With ordinal data, we are able to both categorize and rank the data with respect to some characteristic or trait. With data on an interval scale, not only can we categorize and rank the data, but we are also assured that the differences between scale values are meaningful. Ratio-scaled data have all the characteristics of interval-scaled data as well as a meaningful zero point, which allows us to interpret the ratios of values. 67. Gender: nominal; Age: ratio; Smoking: nominal; Number of cigarettes per day: ratio; Time of smoking: ratio Feedback: A variable whose values are described verbally is qualitative, while a variable that assumes meaningful numerical values is quantitative. The categories for qualitative nominal data do not have any natural ordering, while such an ordering is visible for qualitative ordinal data. A quantitative data with a ratio scale of measurement has a meaningful zero point, and hence all ratio values are naturally interpretable. Nominal: Town and Class; Interval: Date; Ratio: Price and Assessment Town categories: Avalon, Wildwood, and North Wildwood; Class categories: Residential and Commercial 68. Qualitative variables: Town, Class; Quantitative variables: Date, Price, Assessment Feedback: A variable whose values are described verbally is qualitative, while a variable that assumes meaningful numerical values is quantitative. The categories for nominal data do not have any natural ordering, while such an ordering is visible for ordinal data. A quantitative data with a ratio scale of measurement has a meaningful zero point, and hence all ratio values are naturally interpretable. Nominal: School; Ordinal: Degree; Ratio: Years Experience, Classes Taught, and Salary Categories for School: Brookside E.S., Program 3-Emotionally Distur., Program 5-Life Skills, and Berger Academies-Hackensack; Categories for Degree: Bachelors and Masters 69. Qualitative: School, Degree; Quantitative: Years Experience, Salary, Classes Taught