homework2 - Stat 665 (Spring 2011) Kaizar Homework 2 Due at...

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Unformatted text preview: Stat 665 (Spring 2011) Kaizar Homework 2 Due at the beginning of class, Friday April 15 . Aim of Homework : To think about different kinds of categorical data. To apply different measures of association in two-way tables. To perform tests of independence. Reading : An Introduction to Categorical Data Analysis, 2nd edition: Sections 2.1-2.6. Exercises : 40 points total 1. (8 points) Agresti 2.16 2. (8 points) Effect Size Measures and Tests of Independence This question relates to data reported in: Nasar J, Hecht P and Wener R. ‘Call if You Have Trouble’: Mobile Phones and Safety among College Students. International Journal of Urban and Regional Research 2007; 31(4): 863-73. For this research, a survey center at The Ohio State University randomly sampled 264 students who carry cell phones to answer a survey (consider this number to be fixed). Of these, 45.9% happened to be female. The results section reported: A higher percentage of females (42.1%) than males (27.9%) reported walking [with their cell phone] somewhere after dark they would not normally go [if they did not have their cell phone with them]. In this question, I would like you to analyze the data to determine if there is a relationship be- tween gender and whether or not the students would walk somewhere they would not normally go. (a) What kind of sampling distribution does this study’s data approximatly follow? (b) From the reported conditional and marginal sample proportions, reconstruct the approx- imate 2x2 table of counts for gender and walking. (Note that due to rounding error, this will not be exact, but your table should only contain whole numbers!) (c) Using the table you constructed, estimate 95% confidence intervals for the difference of proportions, relative risk, and odds ratio. For the relative risk and odds ratio, create aproportions, relative risk, and odds ratio....
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This note was uploaded on 07/26/2011 for the course STA 665 taught by Professor Staff during the Spring '10 term at Ohio State.

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homework2 - Stat 665 (Spring 2011) Kaizar Homework 2 Due at...

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