Homework 9-12 Here are four populations and a potential sample frame for each one. With each pair, identify (1) members of the population who are not in the sample frame; and, (2) sample frame items that are not part of the population. Also, for each one, would you judge the amount of sample frame error to be acceptable or unacceptable. Population Sample Frame a. Buyers of scope mouthwash Email list of Consumer Reports subscribers b. Subscribers to Sirius XM satellite radio State registration records of new automobile buyers c Prospective buyers of a new client and prospective client's tracking software product Member of Sales and Marketing Executives International, a national organization of sales managers d. Users of weatherproof decking materials (to build outdoor decks) Individual's names registered at a recent home and garden show Example: Population: WMU students Sample Frame: WMU Telephone/Address Directory (1) WMU students who are not listed in the WMU directory (i.e., opt-outs, transfer students, graduates) (2) People listed in the WMU directory who are not WMU students (.e., professors, staff, and other non- students) The sample frame error would be acceptable/unacceptable (choose one) because.... 9-13 4 A market researcher is proposing a survey for the Big Tree Country Club, a private country club that is contemplating several changes in its layout to improve its golf course. The research is considering three different sample designs as a way to draw a representative sample of the club's golfers. The three designs are: a. Station an interviewer at the first hole tee on a day chosen at random, with instructions to ask every 10th golfer to fill out a self-administer questionnaire. b. Put a stack of questionnaires on the counter where golfers check in with a sign offering a free dinner in the clubhouse for 3 players who fill out the questionnaire and have their names selected by lottery. c. Use the city telephone directory to conduct a 1-plus dialing procedure. With this procedure, a random page in the directory is selected and a name chosen from it, both using a table of random numbers. A "1" would be added to that phone number and every one listed after it, until 1,000 golfers are identified and interviewed by telephone. Assess the representativeness and other issues associated with this sample problem. Be sure to identify the sample method being contemplated in each case. Which sample method do you recommend using (a, b or c) and why? 10-5 Using the formula provided in your text, determine the approximate sample sizes for each of the following cases all with the precision (allowable error) of +/-5%: (Remember to round up). a. Variability of 30%, confidence level of 95% b. Variability of 60%, confidence level of 99% c. Unknown variability, confidence level of 95% 10-13 Here are some numbers you can use to sharpen your computational skills for sample size determination. Crest is reviewing plans for its annual survey of purchasers of its 3D White toothpaste brand. With each case in the following table, calculate the sample size pertaining to the key variable under consideration. Where information is missing, provide reasonable estimates. Key variable Variability Acceptable Confidence Level Error a. Market share of Crest 3D white toothpaste last paste 23% share 4% 95% year b. Percent of people who brush their teeth per Unknown 5% 99% week 30% switched last 5% 95% c. How likely Crest 3D White buyers are to switch brands year 3.5% 95% d. Percent of people who want tooth whitening features in their toothpaste 20% two years ago; 40% one year ago Unknown e. 6% 99% Willingness of people to adopt the toothpaste brand recommend by their family dentist