Practice B
Name———————————————————————— Lesson Lesson 6.4 6.4 Date ————————————— Practice B For use with the lesson “Select and Draw Conclusions from Samples” Identify the type of sample described. Then tell if the sample is biased. Explain your reasoning. 1. A consumer advocacy group wants to know if car owners believe their car is reliable. The group randomly selects 1020 car owners and mails out a survey to each one. 2. A grocery store wants to know which day of the week consumers prefer to do their grocery shopping. Everyone who shops at the store on Friday is asked which day of the week they prefer to do their grocery shopping. 3. A survey of students’ favorite school subjects is being conducted. Every other student in the math club is asked “Which school subject is your favorite?” Find the margin of error for a survey that has the given sample size. Round your answer to the nearest tenth of a percent. 4. 200 5. 350 8. 5200 9. 495 6. 1100 10. 280 7. 2600 11. 9000 12. 62% 13. 64% 14. 69.5% 15. 62.7% 16. 64.5% 17. 60.5% 18. 63.6% 19. 67.5% In Exercises 20 and 21, use the following information. Technology Survey In a survey of 504 people in the United States, about 11% said that the influx of new technologies such as computers has left them feeling overwhelmed. 20. What is the margin of error for the survey? Round your answer to the nearest tenth of a percent. 21. Give an interval that is likely to contain the exact percent of all people in the United States who feel overwhelmed by the influx of new technologies. In Exercises 22–25, use the following information. TV in the Bedroom A survey reported that 510 kids ages 8 to 18, or 68% of those surveyed, have a TV in their bedroom. 22. How many kids ages 8 to 18 were surveyed? 23. What is the margin of error for the survey? Round your answer to the nearest tenth of a percent. 24. Give an interval that is likely to contain the exact percent of all kids ages 8 to 18 who have a TV in their bedroom 25. About how many kids ages 8 to 18 should be surveyed to have a margin of error of 2.5%? 6-42 Algebra 2 Chapter Resource Book Copyright © Houghton Mifflin Harcourt Publishing Company. All rights reserved. Find the sample size required to achieve the given margin of error. Round your answer to the nearest whole number. Lesson 6.3 Use Normal Distributions, continued 5. 0.051 Practice Level A Real-Life Application Challenge Practice x 2 }x 1. z 5 } s zs 5 x 2 }x } x 1 zs 5 x x 5 }x 1 zs 2. $50.80 is below the mean, $77.80 is above the mean, $61.60 is above the mean. 3. a. 75.8% b. about 505 4. 2.87%; yes, because only 2.87% of light bulbs have a life span of more than 3085 hours. 5. a. 0.6 b. 22.1 c. A 5 84.1, B 5 78.5, C 5 71.5, D 5 65.9 Lesson 6.4 Select and Draw Conclusions from Samples Teaching Guide Copyright © Houghton Mifflin Harcourt Publishing Company. All rights reserved. 1. Check student responses. 2. Sample answer: It can change the results to a more favorable or less favorable majority if the people surveyed are not randomly chosen. Most teachers would say “yes.” Most students would say “no.” 3. Sample answer: The more people surveyed, the more likely the survey will yield meaningful results; 100 students in hall; the first sample is very small, and if they are eating in the cafeteria, chances are they like the food. Graphing Calculator Activity 1. Sample answer: Make a list of the 57 employees, and assign each of these employees a different number from 1 to 57. Generate 12 unique random integers from 1 to 57. For each number that is generated, circle the corresponding employee on your list. If a number is repeated, simply discard it and generate a new, unique number. 1, 13, 14, 16, 29, 39, 41, 45, 47, 48, 53, 56 2. Sample answer: Make a list of the 249 members, and assign each of these members a different number from 1 to 249. Generate 25 unique random integers from 1 to 249. For each number that is generated, circle the corresponding 1. systematic; biased; People attending a baseball game may be likely to say baseball is their favorite sport. 2. self-selected; unbiased; People entering a pet store would not be biased toward any one particular animal. 3. convenience; biased; Members leaving an aerobics class are more likely to attend aerobics classes than other members. 4. 66.7% 5. 610.0% 6. 64.0% 7. 61.7% 8. 61.5% 9. 63.6% 10. 65.1% 11. 61.1% 12. 204 people 13. 278 people 14. 156 people 15. 123 people 16. 816 people 17. 2066 people 18. 434 people 19. 3460 people 20. 63.5% 21. between 12.5% and 19.5% 22. Sample answer: Assign each person a number from 1 to 15,000 and use a random number generator to generate 800 unique numbers. 23. Sample answer: Selecting people who currently have children attending a school in the school district. 24. Sample answer: Mailing a survey to each person and then counting the first 800 that are received (self-selected). answers 1. 2.5% 2. 95% 3. 0.815 4. 0.000625 member on your list. If a number is repeated, simply discard it and generate a new, unique number. 45, 74, 75, 77, 83, 94, 98, 126, 129, 143, 148, 151, 155, 157, 161, 179, 189, 190, 192, 204, 213, 221, 226, 245, 247 Practice Level B 1. random sample; unbiased; The sample is representative of the population (car owners). 2. convenience sample; biased; Consumers shopping on a Friday probably prefer to shop on that day. 3. systematic; biased; Students in the math club are more likely to prefer math than other students. 4. 67.1% 5. 65.3% 6. 63.0% 7. 62.0% 8. 61.4% 9. 64.5% 10. 66.0% 11. 61.1% 12. 2500 13. 625 14. 111 15. 1372 16. 494 17. 40,000 18. 772 19. 178 20. 4.5% 21. between 6.5% and 15.5% 22. 750 23. 3.7% 24. between 64.3% and 71.7% 25. 1600 Algebra 2 Chapter Resource Book A19
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