1. What are the two main branches of statistics? 2. A statistic is a measure that de- scribes a population characteristic. Descriptive statistics and
... [Show More] inferential statistics False. A statistic is a measure that describes a sample characteristic 3. How is a sample related to a populaA- tion? sample is a subset of a population. 4. What is the difference between a pa- rameter and a statistic? 5. A population is the collection of A parameter is a numerical descrip- tion of a population characteristic. A statistic is a numerical description of a sample characteristic. False. A population is the collection some outcomes, responses, mea-of all outcomes, responses, mea- surements, or counts that are of in- terest. 6. Why is a sample used more often than a population? 7. A sample statistic will not change from sample to sample. 8. Determine whether the data set is a population or a sample. Explain your reasoning. The salary of each teacher in a school. 9. Determine whether the data set is a population or a sample. Explain your reasoning. The salaries of 5 baseball players on a team of 25 10. Venn diagram: The ages of home- owners in a certain country box with surements, or counts that are of in- terest. It is usually impossible to count the entire population. The statement is false. A sample statistic can change from sample to sample. Population, because it is a collec- tion of salaries for all teachers in the school. Sample, because the collection of salaries for 5 baseball players is a subset of all baseball players on the team. Population: The ages of home own- ers in the country. blue box inside with the ages of home Sample: The ages of home owners in owners in the country who have a mortgage. 11. A survey of 12,076 adults in a particu- the country who have a mortgage. Population: The immunization status lar country found that 47.8 % receiveodf all adults in the country. an influenza vaccine for a recent flu season. Identify the population and the sample. Sample: The immunization status of the 12,076 adults selected. 12. A quality-control manager random-Population: All bottles of vinegar pro- ly selects 30 bottles of vinegar that were filled on August 15 to assess the calibration of the filling machine. duced in the plant on August 15. Sample: The 30 bottles of vinegar selected in the plant on August 15. 13. A survey of third- to twelfth-gradePopulation: The time spent per day students with a sample size of 2007 found that they devoted an average of 2 hours and 24 minutes per day to using entertainment media. Identify the population and the sample. 14. Determine whether the underlined value is a parameter or a statistic. Upper A study of 6 comma 076 adults in public rest rooms found that Modi- fying 23 % (23% is underlined) did not wash their hands before exiting. 15. Determine whether the number de- scribes a population parameter or a sample statistic. Explain your rea- soning. A survey of 2207 adults in a coun- on using entertainment media by all third- through twelfth-graders Sample: The time spent per day on using entertainment media by the 2007 third- through twelfth-graders sampled Statistic The number is a sample statistic be- cause it describes the people in a sample, which is a subset of all of the people in the country. try found that 79 % think that militant terrorists are a major threat to the well-being of their country. 16. 16. Suppose a survey of 517 women in the United States found that more than 58 % are the primary investor in their household. Which part of Descriptive Statistic: 58% of women in the sample are the primary in- vestor in their household. Inference: There is an association the survey represents the descriptive between U.S. women and being the branch of statistics? Make an infer-primary investor in their household. ence based on the results of the sur- vey. 17. Suppose a survey of 931 car buy- Descriptive Statistic: 24% of car buy- ers found that more than 24 % boughetrs in the sample bought leather leather seats. Which part of the survey represents the descriptive seats. Inference: Most car buyers do not branch of statistics? Make an infer-buy leather seats. ence based on the results of the sur- vey. 18. For data at the interval level, you canT-he statement is false. A true state- not calculate meaningful differences ment is "For data at the interval leve between data entries. 19. Select all the levels of measurement for which data can be qualitative. 20. More types of calculations can be performed with data at the nominal level than with data at the interval level. 21. Data at the ordinal level are quantita- tive only. 22. Data at the ratio level cannot be put in order. 23. Select all the levels of measurement for which data can be quantitative. you can calculate meaningful differ- ences between data entries." Ordinal and Nominal. False. More types of calculations can be performed with data at the interval level than with data at the nominal level. False. Data at the ordinal level can be qualitative or quantitative. The statement is false. A true state- ment is "Data at the ratio level can be placed in a meaningful order." Ordinal, Ratio and Interval. 24. Goals scored in a hockey game. Is the variable qualitative or quantita- tive? The variable is quantitative because goals scored is found by measuring or counting. 25. Places of birth The variable is qualitative because places are attributes or labels. 26. Favorite musical style The variable is qualitative because a favorite music style describes an attribute or characteristic. 27. Distances between fence posts The variable is quantitative be- cause places are numerical mea- surements. 28. Weight The variable is quantitative because weight is found by measuring or counting. 29. The masses (in grams) of a sample of a species of fish caught in the waters of a region are shown below. Deter- mine the level of measurement of the data set. 30. The jersey number for players on a basketball team are listed below. Identify the level of measurement of the data set. 31. The list of books that your friend read for school for the past five months is shown below. 32. The following appear on a physi- cian's intake form. What is the lev- el of measurement for weight? Pain level (scale of 0 to 10)? Marital sta- tus? Temperature? Age? Happiness Ratio. The data can be ordered and differences between data entries are meaningful, and a zero entry is an inherent zero. Nominal. The data are categorized using numbers, but no mathematical computations can be made. Nominal. Weight: Ratio Pain scale: Ordinal Marital status: Nominal Temperature: Interval Age: Ratio Happiness level: Ordinal level? Disabilities? Change in health (scale of -5 to 5)? 33. The region of a country with the high- est level of food production for the past six years is shown below. 34. The height (in inches) of a sample of a species of tree two years after being planted are shown below. 35. Determine whether the underlined numerical value is a parameter or a statistic. Explain your reasoning. The average grade on the midterm exam in a certain math class of 50 students was an Modifying 88 with underline . 36. The region of a country with the high- est level of coal production for the past six years is shown below. 37. What is the difference between an Disabilities: Nominal Change in health: Ordinal Qualitative. Nominal. Quantitative. Ratio. Parameter, because the data set of all 50 midterm exams in the math class is a population. Qualitative. Nominal. In an experiment, a treatment is ap- observational study and an experi- plied to part of a population and ment? 38. What is the difference between a cen- sus and a sampling? 39. What is the difference between a ran- dom sample and a simple random sample? responses are observed. In an ob- servational study, a researcher mea- sures characteristics of interest of a part of a population but does not change existing conditions. A census includes the entire popula- tion. A sampling includes only part of the population. With a random sample, each indi- vidual has the same chance of be- ing selected. With a simple random sample, all samples of the same size have the same chance of being se- lected. 40. What is replication in an experimentR?eplication is repetition of an experi- Why is replication important? 41. Using a systematic sample guaran- tees that members of each group within a population will be sampled. 42. *The method for selecting a stratified sample is to order a population in some way and then select members of the population at regular intervals. ment under the same or similar con- ditions. Replication is important be- cause it enhances the validity of the results. False. Using a stratified sample guar- antees that members of each group within a population will be sampled. False. The method for selecting a systematic sample is to order a pop- ulation in some way and then select members of the population at regular intervals. 43. In a survey of 1354 adults in a counT- he study is observational because try, 51 % said the country's leaderit does not apply a treatment to the should release all medical informa- tion that might affect their ability to serve. 44. A pharmaceutical company wants to test the effectiveness of a new al- lergy drug. The company identifies adults. a) The experimental units are the 30 - 35 year old females being given the treatment. The treatment is the new 250 females 30-35 years old who sufa-llergy drug. fer from severe allergies. The sub- jects are randomly assigned into two groups. One group is given the new allergy drug and the other is given a placebo that looks exactly like the b) There may be a bias on the part of the researcher if the researcher knows which patients were given the real drug. c) The study would be a double-blind new allergy drug. After six months, study if both the researcher and the the subjects' symptoms are stud- patient did not know which patient ied and compared. Answer parts (a)received the real drug or the placebo. through (c) below. (a) Identify the experimental units and treatments used in this experi- ment. Choose the correct answer be- low. (b) Identify a potential problem with the experiment design being used and suggest a way to improve it. (c) How could this experiment be de- signed to be a double-blind? 45. Use the row of numbers shown below to generate 12 random numbers be- tween 01 and 99. 14055 33536 73920 12972 10903 91693 46591 83475 Starting at the beginning of the row, what are the first 12 numbers be- tween 01 and 99 in the sample? 46. In 1965, researchers used random digit dialing to call 1500 people and ask what obstacles kept them from attending town hall meetings. What type of sampling was used? What po- (Take each number in 2's (14, 05, 53 etc.)) Simple random sampling was used, since each number had an equal chance of being dialed, so all sam- ples of 1500 phone numbers had an equal chance of being selected. tential sources of bias were present, if any? Select all that apply. Bias: Telephone sampling only in- cludes people who had telephones. People who owned telephones may have been older or wealthier on av- erage, and may not have been rep- resentative of the entire population. Individuals may have refused to par- ticipate in the sample. This may have made the sample less representative of the population. Individuals may have not been avail- able when the researchers were 47. Questioning students as they leave calling. Those individuals that were available may have not been repre- sentative of the population. Convenience sampling is used, be- an academic building , a researcher cause students are chosen due to asks 339 students about their dat- ing habits. What potential sources of bias are present, if any? convenience of location. Bias: The sample only consists of members of the population that are easy to get. These members may not be representative of the population. Because of the personal nature of the question, students may not an- swer honestly. 48. Lettuce is planted on a 50 -acre fieldS. tratified sampling is used, since the The field is divided into one-acre subplots. A sample is taken from field is divided into subplots and a random sample is taken from each each subplot to estimate the harvest. subplot. Bias? Bias: Certain subplots may have more or fewer lettuce plants than others. Samples from these subplots may bias the overall sample. 49. The average age of the 50 employees The study is a census , because the of a company. population is small enough for it to be practical to record all of the respons- es. 50. Why is eating eggs bad for you? The question is biased. The wording "How do you think eating eggs af- fects your health?" would be better. 51. How often do you eat ice cream dur- ing an average month ? 52. Class boundaries ensure that con- secutive bars of a histogram touch. No, because it does not lead the re- spondent to any particular answer. True 53. 53. In a frequency distribution, the clasFsalse. In a frequency distribution, the width is the distance between the lower and upper limits of a class. 54. What are some benefits of represent- class width is the distance between the lower or upper limits of consecu- tive classes. Organizing the data into a frequency ing data sets using frequency distrid- istribution can make patterns within butions? 55. What are some benefits of using the data more evident. It can be easier to identify patterns of graphs of frequency distributions? a data set by looking at a graph of the frequency distribution. 56. After constructing a relative fre- quency distribution summarizing IQ scores of college students, what If percentages are used, the sum should be 100%. If proportions are used, the sum should be 1. should be the sum of the relative fre- quencies? 57. What is the difference between rel- Relative frequency of a class is the ative frequency and cumulative fre-percentage of the data that falls in quency? 58. The midpoint of a class is the sum of its lower and upper limits divided by two. 59. What is the difference between class limits and class boundaries? 60. 60. that class, while cumulative frequen- cy of a class is the sum of the fre- quencies of that class and all previ- ous classes. True Class limits are the least and great- est numbers that can belong to the class. Class boundaries are the num- bers that separate classes without forming gaps between them. For in- teger data, the corresponding class limits and class boundaries differ by 0.5. An ogive is a graph that displays rel- ative frequencies. 61. What is the difference between a fre- quency polygon and an ogive? 62. Why should the number of classes in a frequency distribution be between 5 and 20? The statement is false. An ogive is a graph that displays cumulative fre- quencies. A frequency polygon displays class frequencies while an ogive displays cumulative frequencies. If the number of classes in a frequen- cy distribution is not between 5 and 20, it may be difficult to detect any patterns. [Show Less]