252x0711 1 20 07 Open in Print Layout format ECO252 QBA2 FIRST HOUR EXAM February 23 2007 Version 1 Name Show your work Make Diagrams Exam is normed on 50 points Answers without reasons are not usually acceptable I 8 points Do all the following x N 2 7 1 P 23 4 x 2 2 P 7 x 7 3 P x 0 4 x 085 Do not try to use the t table to get this 252x0711 1 20 07 Open in Print Layout format II 9 points 2 point penalty for not trying part a Edwin Mansfield tells us that in order to compute information about the average expenditure by honors students at Semiconscious State University a sample of four students expenditures is taken The results are as below I should not have to tell you that parts b c and f require hypothesis tests x 192 150 168 90 a Compute the sample standard deviation s of expenditures Show your work 2 b Is the population mean significantly above 130 Use a 90 confidence level Show your work 3 c Redo b when you find out that there are only 10 honors students at Semiconscious State University 2 d Extra Credit Find an approximate p value for your null hypothesis 2 e Assume that the population standard deviation is 40 and create an 83 two sided confidence interval for the mean 2 17 f Extra Credit Given the data test the hypothesis that the population standard deviation is above 40 252x0711 1 20 07 Open in Print Layout format III Do as many of the following problems as you can 2 points each unless marked otherwise adding to 13 points Show your work except in multiple choice questions Actually it doesn t hurt there either If the answer is None of the above put in the correct answer 1 Which of the following is a Type 1 error a Rejecting the null hypothesis when the null hypothesis is false b Rejecting the null hypothesis when the null hypothesis is true c Not rejecting the null hypothesis when the null hypothesis is true d Not rejecting the null hypothesis when the null hypothesis is false e All of the above f None of the above 2 In a survey 540 out of 1000 respondents indicated that they would rather have 150 than a day off You believe that a majority over 50 will prefer the money to the day off Do the data support your opinion Your hypotheses are a H 0 p 50 H 0 p 50 b H 0 p 50 H 0 p 50 c H 0 p 50 H 0 p 50 d H 0 p 50 H 0 p 50 e H 0 p 50 H 0 p 50 f None of the above 3 The chi squared distribution is used in which of the following circumstances a We are testing a single mean the underlying distribution is Normal and the population variance is unknown b We are testing a single variance the underlying distribution is Normal and the population variance is unknown c We are testing a single proportion the underlying distribution Binomial and we have a large sample d We are testing a single median the underlying distribution is Normal and the population variance is unknown e None of the above 6 252x0711 1 20 07 Open in Print Layout format 4 According to Dummeldinger The Florida Association of Retired Teachers FART is thinking of changing its name It takes a survey of 60 members and finds that many wish to change the name Assuming that the alternative hypothesis is H1 p 6 and that 01 how many people what proportion of 60 would be required to reject the null hypothesis Show your work 3 9 5 According to Dummeldinger The Florida Association of Retired Teachers FART is thinking of changing its name It takes a survey of 60 members and finds that 45 wish to change the name Assuming that the alternative hypothesis is p 6 what is the p value for the null hypothesis 3 12 6 Given the numbers in problem 5 create a 95 two sided confidence interval for the proportion that favors a change 3 15 252x0711 1 20 07 Open in Print Layout format 7 Assuming that about 60 of the old FART members favor a name change how many members would we have to poll to know what the proportion is within 01 2 17 8 While we are playing with old folks in Florida assume that a Florida town has had a median age of 55 Because they are afraid that the median age is now higher the planning board takes a sample of 200 people How many of the 200 people would have to be over 55 for the planning board to conclude that the median has risen 3 20 252x0711 1 20 07 Open in Print Layout format Blank page for calculations 252x0711 1 20 07 Open in Print Layout format ECO252 QBA2 FIRST EXAM February 23 2007 TAKE HOME SECTION Name Student Number and class IV Do at least 3 problems at least 7 each or do sections adding to at least 20 points Anything extra you do helps and grades wrap around Show your work State H 0 and H 1 where appropriate You have not done a hypothesis test unless you have stated your hypotheses run the numbers and stated your conclusion Use a 95 confidence level unless another level is specified Answers without reasons usually are not acceptable Neatness and clarity of explanation are expected This must be turned in when you take the in class exam Note that answers without reasons and citation of appropriate statistical tests receive no credit Many answers require a statistical test that is stating or implying a hypothesis and showing why it is true or false by citing a table value or a p value If you haven t done it lately take a fast look at ECO 252 Things That You Should Never Do on a Statistics Exam or Anywhere Else All problems are based on Anderson Sweeny and Williams except 4f and 4g 1 The average sales of a grocery store have been 80000 per day After new advertising policies are adopted sales in thousands of dollars are tabulated for 64 days Test to see if the average sales are now above 80000 x 69 07 109 29 84 73 75 51 78 99 72 72 76 23 52 80 81 67 88 30 86 43 81 79 68 74 91 19 83 13 87 95 72 69 75 33 103 18 64 20 92 14 87 70 78 09 74 41 72 73 86 89 90 65 86 96 68 47 85 43 85 03 92 67 82 26 83 34 63 91 83 54 72 60 78 85 66 50 69 59 83 59 80 67 65 65 91 22 81 44 82 75 91 43 91 48 87 44 83 41 93 22 91 05 82 13 91 84 97 30 75 19 94 47 96 50 71 65 91 50 76 37 95 71 …
View Full Document
Unlocking...