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Unformatted text preview: Midterm One Friday the 2nd of February, 2007 Name: General Comments: • This exam is closed book. However, you may use two pages, front and back, of notes and formulas. Write your answers on the exam sheets. If you need more space, continue your answer on the back of the page. A normal table and a chi-squared table are attached at the end. Make sure you have all 13 pages! • The exam is 110 minutes long. There are 4 questions, worth a total of 100 points. They are not equally weighted, nor are they of equal difficulty. The number of points each question is worth is printed with the problem. Read the questions carefully. If you are unsure of the interpretation, come ask. • You must show your work to obtain full credit. If you use a result from class, state what result you are using. If you can’t complete a problem for any reason, explain what concepts are at issue, and how you would attack the problem. If you can’t work out a number you need for a later part of a problem give it a symbol and show how you would do the calculations with a symbol in place of the missing number. It is a good idea to explain your reasoning briefly in English. If I can’t tell that you understood what you were doing, I can’t give you credit, particularly if you get the wrong numerical answer. GOOD LUCK! Question Total Points Score Number Possible Received 1 33 2 15 3 12 4 40 Total 100 THE STORY BEHIND THE EXAM: Pete’s Powerful Pills (PPP) and Martha’s Miracle Medicines (MMM) are rival pharmaceutical companies in the city of Los Seraphim. Recently each has developed a new vaccine which is supposed to prevent Statisticitis, a disease that commonly afflicts statistics students at the local school, the University of Calculationally Learned Adults. During the exam we will try to evaluate which vaccine works better and learn a little more about the disease. 1 Question 1: Cures on Contingency (33 points, 40 minutes) An independent testing agency runs a study to compare the PPP and MMM vaccines to see if they have different rates of effectiveness. They interview a total of 200 students who have taken one of the vaccines and record whether or not they have gotten statisticitis. A STATA printout for their study analysis is given below, although it seems to have some pieces missing. Use the printout to answer the following questions: . tabi 5 15\95 85, exp chi2 e Expected counts are printed below observed counts...
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This note was uploaded on 03/05/2008 for the course BIOSTAT 100B taught by Professor Sugar during the Winter '07 term at UCLA.
- Winter '07