4. Which question is the least biased?

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1 Algebra II Chapter 10 Statistics Review 1. A hardware store wants to know what people think of the store. A note with a telephone number to call to respond to a survey and enter a contest is printed on each cash register receipt. Determine the population and the sample. Population: Sample: 3. A school newspaper reporter wants to do a survey to predict who will win the next school election. Which method might give the least biased sample? A. Survey one student from each table in the cafeteria during lunch. B. Survey one student from each fourth-period class. C. Survey all of the members of the current student government. D. Survey the members of the sports teams. 5. In an unbiased survey of 75 of a high school s 1100 students, 55 say they participate in at least one after-school activity. Predict the number of students at the school who participate in at least one after-school activity. Name 2. The student council wants students to help decide on a theme for a costume dance. Students can choose movies, famous historical figures, or sports and games. What is the population for this survey? A. student council B. students C. students and teachers D. students, teachers, and parents 4. Which question is the least biased? A. Do you support the mayor's proposal to enlarge the city park? B. Do you support the mayor's proposal to enlarge the city park by reducing available parking? C. Do you support the mayor's proposal to enlarge the city park and give our city more clean, green space? D. Do you support the mayor's proposal to enlarge the city park by removing part of the mall? 6. In an unbiased survey of 40 of a company s employees, 25 responded that they considered it very important that the amount of vacation time be increased. The company has 825 employees. Predict how many employees at the company believe it very important that vacation time be increased. 7. You are conducting a survey of opinions about selecting a new school song. Which method is least likely to result in a biased sample? 8. In an unbiased sample of 50 students in a school, 18 said that they own more than 10 movies. There are 1440 students at the school. Predict the number of students who own more than 10 movies. A. Survey 25 females in your grade. B. Survey 25 males in your grade. C. Survey each student in your music class. D. Survey 25 students chosen in a drawing. Identify the type of sample described (random, systematic, self-selected, or convenience) for #9-14. Then tell if the sample is biased. Explain your reasoning. 9. A team wants to know who the fans think was the team's most valuable player during the season. Fans can vote on the team's website. 10. The managers of a movie theater chain want to find the number of movies people in the community usually see in a theater each month. The managers have the ticket sellers at each theater survey customers when they purchase their tickets.

2 11. The managers of a company with 500 employees want to know how the employees feel about some proposed changes to employee policies. The managers use a computer to generate a list of 50 employees to survey from a database that includes all of the employees. 12. Every 10 th ipod coming off an assembly line is checked for defects. 13. A door prize is given away at a home improvement seminar. Tickets are placed in a bin, and the tickets are mixed up. Then a ticket is selected by a blindfolded person. 14. The first 25 adults leaving a grocery store are asked how much money they spend per week on entertainment. Find the margin of error for a survey that has the given sample size. Round your answer to the nearest tenth of a percent. Use the margin of error formula given below: 1 n Find the sample size required to achieve the given margin of error. Round your answer to the nearest whole number % % Use each description to answer the questions A market research company surveys a randomly chosen sample of 7500 adults and finds that 62% prefer the taste of its energy drink over the taste of a competitor s energy drink. What is the margin of error? To the nearest tenth of a percent, what is the margin of error in a random sample of 160 people chosen from a large population?

3 21. A new medically approved wheelchair was considered to be an improvement over a standard wheelchair by 325 out of 450 patients in a survey. a. What is the margin of error for the survey? Round your answer to the nearest tenth of a percent. b. Give an interval that is likely to contain the exact percent of all patients who would consider the new wheelchair an improvement. 22. Suppose that in a random sample of 800 phone company customers, 41.5% say they are dissatisfied with their service. a. What is the margin of error for the survey? Round your answer to the nearest tenth of a percent. b. Give an interval that is likely to contain the exact percent of the company s customers who are dissatisfied. Find the best answer for each multiple choice question. 23. In a survey of 400 retirees, 35% said they had modest savings. What is the margin of error for the survey? Give an interval that is likely to contain the actual percent of all retirees who would say they have modest savings. A. B. C. D. 24. In a survey of 2500 voters, 32% favor the new law. What is the margin of error for the survey? Give an interval that is likely to contain the percent of all voters who favor the new tax law. A. B. C. D. Calculate the following values for the weights of the players on each of two college football teams Mean: Median: Range: Mean: Median: Range: Mode: Mode: 27. How does the mean help you compare the weights of the players on these two teams?

4 Identify the outlier of the data set. Then find the mean, median, mode, and range of the data set when the outlier is included and when it is not. 28. Data: 10.9, 12.4, 0.7, 11.6, 12.8, 11.6 Outlier: Calculate with the outlier: Mean: Median: Mode: Range: Calculate without the outlier: Mean: Median: Mode: Range: 29. Which of the above measures are MOST affected by the outlier? 30. A hen lays 10 eggs during one week. The weights of the eggs (in grams) are recorded. The hen is then placed on a different diet. Suppose the weights of 10 eggs laid several weeks later increased by 6 grams. The data is shown below. Before: 34, 35, 37, 38, 41, 43, 43, 45, 46, 48 After: 40, 41, 43, 44, 47, 49, 49, 51, 52, 54 Compare the mean, median, mode, and range of the "before" data and the "after" data. A. The mean, median, and mode each increased by 5, but the ranges increased by 5. B. The mean, median, and mode each increased by 6, but the ranges increased by 5. C. The mean, median, and mode each increased by 5, but the ranges are the same. D. The mean, median, and mode each increased by 6, but the ranges are the same. Find each of the following measures from the data set and then construct a box-and-whisker plot. Don t forget to include the number line with your plot. The data sets do not contain an outlier , 78, 68, 96, 99, 84, , 45, 37, 43, 10, 34 Median: UQ: LQ: Median: UQ: LQ: Smallest #: Biggest #: Smallest #: Biggest #: Box-and-Whisker Plot: Box-and-Whisker Plot: Find each specified value. 33. Malcolm s mean on five tests is 86. Determine the sum of his scores. 34. Jeremy s mean on six tests is 92. Determine the sum of his scores.

5 35. A mean of 80 or better for five tests is needs for a final grade of a B in Allison s math class. Her first four test grades are 73, 69, 85, and 80. What grade does Allison need on the fifth test to get a B in the course? 36. A mean of 60 on seven tests is needed to pass a college course. On his first six tests, Garrett received grades of 51, 72, 80, 62, 57, and 69. What grade must he receive on his last test to pass the course? 37. Which of the measures of central tendency must be an actual piece of data in the distribution? (mean, median, mode) 38. What is the median of 0.5, 0.6, 0.7, 1.2, 1.5, and 1.5? Use each statistical graph to answer each set of questions. 39. Find each value: Use the following histogram to answer each question. It shows the flight duration information for the missions of one space shuttle. Range Median LQ UQ IQ range 40. Between what interval does the lower 25% of the data lie? 41. Between what interval does the upper 25% of the data lie? 43. How many missions were days long? 44. In which interval was the greatest number of missions? 42. Between what interval does the middle 50% of the data lie? 45. How many more missions were days long than were days long? Plots A and B represent the number of minutes that the students at two schools spend traveling to school. 46. About 50% of the students at school A take fewer than how many minutes to get to school? 47. About 75% of the students at school B take fewer than how many minutes to get to school? 48. At which school is the range of travel times greater? 49. What percent of the students at school B take longer to get to school than any of the students at A?

6 The following pie chart shows the results from asking 250 people their favorite type of movie. 50. What percent of people like comedies the best? 51. What percent of people favor horror movies? 52. If 250 people were asked, approximately how many people favored a comedy? 53. If 250 people were asked, approximately how many people favored a horror? Construct each statistical graph. The ages of the 44 U.S. Presidents at their first inauguration (as of 2011) are: 55. Create a histogram for # Create a frequency distribution with a first class of The ages of the 44 U.S. presidents at their first inauguration (as of 2011) # Presidents (Frequency) 56. Create a frequency polygon for #54.

7 The table below indicates the ages of a sample of 20 guests who stayed at Captain Fairfield Inn Bed and Breakfast Create a stem-and-leaf plot. Don t forget to make a KEY! STEM LEAVES