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Unformatted text preview: Final Exam PracticeANOVA and Logistic Regression General Comments: This file contains some practice problems on ANOVA and logistic regression. For practice on contingency tables, regression, etc. see the practice files from our first two midterms. I posted so many problems then that I dont think it will particularly help to post more! However if there is a topic you feel short of practice on, let me know. You should also look over my solutions to our midterms 1 and 2 as I have a tendency to ask again about things that the class as a whole did poorly on.... I dont guarantee that these problems represent all possible questions I could ask on ANOVA and logistic regression though I do think they are useful in giving you a sense of how I might ask questions. As always, I feel that our homework assignments are the best representation of what I feel is important for our class. In this case HW7 is the key. I have included the warm-up problems from that assignment here for reference. ANOVA (1) ANOVA basics (courtesy of Prof. Afifi): A partly filled in ANOVA table is shown below: Source df SS MS F Between (Treatment) 3 16.42 Within (Error) 102.50 Total 31 (a) Fill in the blanks in the table, and explain what each of the quantities SSB, SSW, MSB, MSW and F tells you. (b) How many treatment groups are there? Briefly explain your reasoning. (c) A completely randomized design is an approach for carrying out an experiment where the treatments are assigned to experimental units (subjects) completely at random. A balanced de- sign is one in which the number of subjects in each treatment group is the same for all treatments. Is it possible that this table was derived from a balanced completely randomized design Explain your reasoning. (d) Obtain an approximate p-value for a test of significance of the hypothesis that all of the treat- ment means are equal. In particular, would you conclude that result is significant at the = . 05 level? (Note: This can be done using an F table or using STATA.) (2) Protein Intake (based on Rosner 12.1-12.5) Researchers compared protein intake among three groups of postmenopausal women: (1) women eating a standard American diet (SRD) (2) women eating a lacto-ovo-vegetarian diet (LAC) and (3) women eacting a strict vegetarian diet (VEG). The mean and standard deviation of protein intake as well as the group sizes are presented 1 in the table below. Use then to answer the following questions: Group Mean SD Number in group STD 75 9 10 LAC 57 13 10 VEG 47 17 6 (a) Perform an overall F test to determine whether there is a significant difference in mean protein intake between the three groups. Be sure you an state the null and alternative hypotheses both mathematically and in words, compute the test statistic by hand, get an approximate p-value, and explain your real-world conclusions....
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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