Second Exam - Statistics 401D/XE Statistical Methods for...

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Statistics 401D/XE Spring, 2008 Statistical Methods for Research Workers Prof. Shelley Second Exam Answer all parts of each of the following problems. Show all of your work, to obtain maximum partial credit. This exam constitutes 25% of the final course grade. Turn in your work by the beginning of class on April 3. You are encouraged to study in groups, but it is expected that the work you turn in is your own. 1. (40 points total; 10 points each part) The table below shows values of life expectancy at birth for selected countries in 2006. (Source: United States Bureau of the Census, International Data Base). Country Males Females (i) Central and South America Brazil 68.02 76.12 Chile 73.49 80.21 Costa Rica 74.43 79.74 Ecuador 73.55 79.43 Guatemala 67.66 71.18 Panama 72.68 77.87 Peru 68.05 71.71 Trinidad and Tobago 65.71 67.86 Uruguay 73.12 79.65 Venezuela 71.49 77.81 (ii) Asia Bangladesh 62.47 62.45 China 70.89 74.46 India 65.66 70.42 Iran 68.85 71.74 Israel 77.33 81.70 Japan 77.96 84.70 Pakistan 62.40 64.44 South Korea 73.61 80.75 Sri Lanka 72.67 76.68 Syria 69.01 71.70 (a) Do these data provide evidence that life expectancy for females in all these countries, on average, is higher than life expectancy for males by at least 5 years? Set up appropriate null and alternate hypotheses to answer this question, indicate clearly how you reached your conclusion, and specify (with diagrams) the critical and calculated values of the test statistic. Use α = .01, and interpret your findings. (b) Do these data show any difference, on average, between life expectancy for females in Asian countries and life expectancy for females in countries of Central and South America? Use α = .01. What do you conclude, and why? (female’s data values in i) and comparing it with female values in ii). (c) The “gender life expectation gap” may be defined as the value of male life expectancy minus female life expectancy within each country . Do these data provide evidence that the gender life expectation gap is higher in Asian countries than in countries of Central and South America? Use α = .01, and interpret your findings. (d) What assumptions are necessary for your test results in parts 1(a)–1(c) of this question to be valid, and what evidence is available regarding whether these assumptions are satisfied or not? (whether these are independent or dependent correlations, use histogram; want visual and numerical) 1
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2. (60 points total; 10 points each part) The SAS program contained in the file (exam2s08.sas) that is printed at the end of this handout uses a data set provided by Alan Agresti to do the following: (a) test for a difference in mean levels of college grade point average between female and male undergraduate students, (b) test for a difference in college and high school grade point averages for each student, (c) provide graphical information related to a possible linear relationship between college grade point average and high school grade point average, (d) use simple linear regression and correlation methods to estimate the
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This test prep was uploaded on 03/26/2008 for the course STAT 401 taught by Professor Shelley during the Spring '08 term at Iowa State.

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Second Exam - Statistics 401D/XE Statistical Methods for...

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