ODD ANSWERS A57 (b) Element Number of elements Elements with Known Properties Metals Rare earth elements Metalloids Other nonmetals Noble gases Halogens 10 20 30 40 50 60 4. (a) x ≈ 1016.4; median = 1019; mode = 1100; The mean or median best describes a typical salary because there are no outliers. (b) Range = 666; s2 ≈ 47,120.9; s ≈ 217.1 (c) CV ≈ 21.4% 5. $150,000 and $210,000 6. (a) Unusual; The z-score is 3, so a new home price of $225,000 is about 3 standard deviations above the mean. (b) Unusual; The z-score is -6.67, so a new home price of $80,000 is about 6.67 standard deviations below the mean. (c) Not unusual; The z-score is 1.33, so a new home price of $200,000 is about 1.33 standard deviations above the mean. (d) Unusual; The z-score is -2.2, so a new home price of $147,000 is about 2.2 standard deviations below the mean. 7. 5 10 15 20 25 35 45 30 40 50 Number of wins Wins for Each MLB Team 35 43 29 19 26 Real Statistics—Real Decisions for Chapter 2 (page 122) 1. (a) Find the average cost of renting an apartment for each area and do a comparison. (b) The mean would best represent the data sets for the four areas of the city. (c) Area A: x = $1131.58 Area B: x = $998.33 Area C: x = $991.58 Area D: x = $1064.17 2. (a) Construct a Pareto chart, because the data are quantitative and a Pareto chart positions data in order of decreasing height, with the tallest bar positioned at the left. (b) Mean monthly rent (in dollars) Area Area A Area D Area B Area C Cost of Monthly Rent per Area 900 1000 800 1100 1200 (c) Yes. From the Pareto chart, you can see that Area A has the highest average cost of monthly rent, followed by Area D, Area B, and Area C. 3. Sample answer: (a) You could use the range and sample standard deviation for each area. (b) Area A Area B range = $467 range = $474 s ≈ $138.45 s ≈ $163.11 Area C Area D range = $518 range = $560 s ≈ $164.51 s ≈ $156.26 (c) No. Area A has the lowest range and standard deviation, so the rents in Areas B–D are more spread out. There could be one or two inexpensive rents that lower the means for these areas. It is possible that the population means of Areas B–D are close to the population mean of Area A. 4. (a) Answers will vary. (b) Location, weather, population Cumulative Review for Chapters 1–2 (page 126) 1. Systematic sampling is used because every fortieth toothbrush from each assembly line is tested. It is possible for bias to enter into the sample if, for some reason, an assembly line makes a consistent error. 2. Simple random sampling is used because each telephone number has an equal chance of being dialed, and all samples of 1090 phone numbers have an equal chance of being selected. The sample may be biased because telephone sampling only samples those individuals who have telephones, who are available, and who are willing to respond. 3. Workplace Fraud Account reconciliation IT controls External audit Notified by law enforcement Confession Document examination By accident Surveillance/ monitoring Internal audit Management review Other means Tip 5 10 15 20 25 30 35 40 45 50 Fraud detection Percent 4. Parameter. The median salary is based on all first-year chemists. 5. Statistic. The percent, 64%, is based on a subset of the population. 6. (a) 95% (b) For $93,500, z ≈ 4.67; For $85,600, z ≈ -0.6; For $82,750, z ≈ -2.5. The salaries of $93,500 and $82,750 are unusual. 7. Population: Collection of opinions of all college students in bachelor’s degree programs. Sample: Collection of opinions of the 3941 college students in bachelor’s degree programs surveyed.
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