Please I need help with 6-20 and 32
UCTION TO STATISTICS 16. Sneakers Nike developed a new type of sneaker designed to help delay the onset of arthritis in the knee. Eighty people with early signs of arth volunteered for a study. One-half of the volunteers wore the experimental sneaker and the other half wore regular Nike sneakers that looked exactly like the experimental sneakers. The individuals wore the sneakers every day. At the conclusion of the study, their symptoms were evaluated and an MRI was performed on their knees. (Source: Washington Post) (a) Identify the experimental units in this experiment. (b) How many treatments are used in this experiment? (c) Identify a potential problem with the experimental design being used and suggest a way to improve it. (d) The experiment is described as a placebo-controlled, double-blind study. Explain what this means. (e) Of the 80 volunteers, suppose 40 are men and 40 are women. How could blocking be used in designing this experiment? Identifying Sampling Techniques In Exercises 17-26, identify the sampling technique used and discuss potential sources of bias (if any). Explain. 17. Using random digit dialing, researchers called 1599 people and asked what obstacles (such as childcare) kept them from exercising. (Source: Yankelovich Partners, Inc. for Shape Up America!) 18. Chosen at random, 500 rural and 500 urban persons age 65 or older were asked about their health and experience with prescription drugs. 19. Questioning students as they left a university library, a researcher asked 358 students about their drinking habits. 20. After a hurricane, a disaster area is divided into 200 equal grids. Thirty of the grids are selected, and every occupied household in the grid is interviewed to help focus relief efforts on what residents require the most. 21. Chosen at random, 1210 hospital outpatients were contacted and asked their opinion of the care they received. 22. For quality assurance, every twentieth engine part is selected from an assembly line and tested for durability. 23. Soybeans are planted on a 48-acre field. The field is divided into one-acre harvest. subplots. A sample of plants is taken from each subplot to estimate the 24. Questioning teachers as they left a faculty lounge, a researcher asked 32 teachers about their teaching styles and grading methods. 25. A list of managers is compiled and ordered. After a starting number is randomly chosen, every ninth name is selected until 1000 managers are selected. The managers are questioned about the use of digital media. 26. From calls made with randomly generated telephone numbers, 1012 respondents were asked if they rented or owned their residence. 27. Sleep Deprivation A researcher wants to study the effects of sleep deprivation on motor skills. Eighteen people volunteer for the experiment Jake, Maria, Mike, Lucy, Ron, Adam, Bridget, Carlos, Steve, Susan Rick, Dan, Kate, Pete, Judy, Mary, and Connie. Use a random number generator to choose 9 subjects for the treatment group. The other 9 subject will go into the control group. List the subjects in each group. T method you used to generate the random numbers.'Iuttt 1 EXPERIMENTAL DESIGN 25 a ll't. \"tritabulary l. W'ltttl is the difference between an observational study and an experiment? 2. What is the diltercnce between a census and a sampling? 3. Describe two methods you can use to generate random numbers. 4. What is replication in an experiment and why is it important? True or False? In Exercises 510, determine whether the statement is true or false. (fit is false. rewrite it as a true statement. 5. In a randomised block design. subjects with similar characteristics are divided into blocks. and then within each bloelt. randomly assigned to treatment groups ti. A double-blind experiment is used to increase the placebo effect. 7. Using a systematic sample guarantees that members of each group within a population will be sampled. 8. A census is a count of part of a population. 9. The method for selecting a stratied sample is to order a population in some way and then select members of the population at regular intervals. I t 10. To select a cluster sample. divide a population into groups and then select all of the members in at least one (but not all) of the groups. Deciding on the Method of Data Collection In Exercises 1114, decide which method of data collusion you would use to collect data for the study. Explain. 11. A study of the effect on the human digestive system of potato chips made with a fat substitute 12. A study of the effect of a product's warning label to determine whether consumers still buy the product 13. Astudycfhowfastaviruswouldspreadinametropolitanarea 14. Astudy of the ages ofthe535 members of the U.S.Congress I Using and Interpreting Concepts 15. Allergy Drug A pharmaceutical company wants to test the effectiveness of a new allergy drug. The company identies 250 females 30-35 years old who suffer from severe allergies. The subjects 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 new subjects symptoms are studied and com (a) Identify the experimental units in this experiment. (b) How many treatments are used in this experiment? allergy drug. After six months, the (c) Identify a potential problem with the experimental design being used and suggest a way to improve it. (d) How could this experiment be designed to be double-blind? SECTION 1.3 EXPERIMENTAL DESIGN 27 28. Random Number Generation Volunteers for an experiment are numbered from 1 to 70. The volunteers are to be randomly assigned to two different treatment groups. Use a random number generator different from the one you used in Exercise 27 to choose 35 subjects for the treatment group. The other 35 subjects will go into the control group. List the subjects, according to number, in each group. Tell which method you used to generate the random numbers. Choosing between a Census and a Sampling In Exercises 29 and 30, determine whether you would take a census or use a sampling. If you would use a sampling, decide what sampling technique you would use. Explain your reasoning. 29. The average salary of the 50 employees of a company 30. The most popular car color among 25,000 students at a university Recognizing a Biased Question In Exercises 31-34, determine whether the survey question is biased. If the question is biased, suggest a better wording. 31. Why is drinking fruit juice good for you? 32. Why are drivers who change lanes several times dangerous? 33. How many hours of sleep do you get on an average night? 34. Do you think the media have a negative effect on teen girls' dieting habits? 35. Writing Television program ratings by Nielsen Media Research are described on page 17. Discuss the strata used in the sample. 36. Writing Television program ratings by Nielsen Media Research are described on page 17. Why is it important to have a stratified sample for these ratings? Extending Concepts 37. Open and Closed Questions Two types of survey questions are open questions and closed questions. An open question allows for any kind of response; a closed question allows only for a fixed response. An open question and a closed question with its possible choices are given below. List an advantage and a disadvantage of an open question. Then list an advantage and a disadvantage of a closed question. Open Question What can be done to get students to eat healthier foods? Closed Question How would you get students to eat healthier foods? 1. Mandatory nutrition course 2. Offer only healthy foods in the cafeteria and remove unhealthy foods 3. Offer more healthy foods in the cafeteria and raise the prices on unhealthy foods 38. Who Picked These People? Some polling agencies ask people to call a telephone number and give their response to a question. (a) List an advantage and a disadvantage of a survey conducted in this manner. (b) What sampling technique is used in such a survey? 39. Give an example of an experiment where confounding may occur. 40. Why is it important to use blinding in an experiment? 41. How are the placebo effect and Hawthorne effect similar? How are they different? 42. How is a randomized block design in experiments similar to a stratified sample? 43. Using Sampling Techniques You have been asked by your school to survey 150 students who use the new fitness center. Describe your procedure for obtaining a sample of each type: random, stratified, cluster, systematic, and convenience
