(a) (b) In 2010, PopCap Games commissioned a survey of adult mobile phone gamers in the United States and in the United Kingdom. A similar survey was also carried out in 2009. Some of the information from the survey is given below: Do you play mobile phone games for less than 60 minutes per week? 2009: Yes (521) Total (659) 2010; Yes (554) Total (814) How often do you typically play on your mobile phone? 2009 2010 Daily 86 284 2-3 times per week 119 296 once a week 59 108 2-3 times a month 72 83 once a month or less 323 43 Total 659 814 464 of the gamers surveyed in 2010 had recommended games to others. This group was asked what inuenced them to recommend a game. They could choose as many answers as they wished. The answers, with the percentages, selecting them were: 33% 38% 49% 86% 40% 36% 45% 41% From a trusted brand Controls simple to use Easy to learn Fun to play Good value Great graphics and sound Is challenging Lots of levels/modes State the sampling situation (a, b or c) for calculating the standard error of the difference in the following scenarios: (i) estimating the difference between the proportion of gamers that played for less than 60 minutes per week in 2009 and the proportion of gamers that played for less than 60 minutes per week in 2010. (ii) estimating the difference between the proportion of gamers that played for at least 60 minutes per week in 2010 and the proportion of gamers that played daily in 2010. (iii) for gamers who recommend games to others, estimating the difference between the proportion of all gamers who, in 2010, would have recommended a game that is fun to play and the proportion of all gamers who, in 2010, would have recommended a game that is easy to learn. Calculate and interpret a 95% confidence interval for the difference between the proportion of gamers that played daily in 2010 and the proportion of gamers that played daily in 2009. Note: You must clearly show that you have followed the \"step-by-step guide to producing a condence interval by hand\" given in the Lecture Workbook, Chapter 6. Use the t-procedures tool to find values for t-multipliers and standard errors. (b) (e) (d) (e) A researcher was interested in Aucklanders' opinions about rates and rate increases. He considered 3 different approaches to gathering information on this. Method 1: Randomly select 1,000 names 'om the Auckland phone book. Then hire a team of people to phone each person on the list and interview them. Method 2: Place advertisements in community papers asking people to go online and ll in a questionnaire. Method 3: Use council records to assemble a list of all houses currently in Auckland City. Randomly select 1,000 houses from this list and post a questionnaire to each address asking the oldest person living in the house to fill in and return the questionnaire. For which of the methods, if any, is non-response bias a potential problem? For which of the methods, if any, is self-selection bias a potential problem? Which of the methods, if any, is subject to interviewer effects? Which of the methods, if any, is subject to sampling errors? For each of the methods, give an example of why there may be selection bias. T499959!" Step-by-Step Guide to Producing a Confidence Interval by Hand . State the parameter to be estimated. (Symbol and words) IS it p. p. #1 - #2. or 91- 92? State the estimate and its value. Write down the formula for a CI, estimate 1 the(estimate), from the Formula Sheet Use the appropriate standard error. (Will be provided) Use the appropriate t-multiplier. (Will be provided) Calculate the confidence limits. (End points of the condence interval) Interpret the interval using plain English. Use the condence limits to construct an answer to the original question in plain English
