Biostatistics Exam 2: Hypothesis Testing and Power Calculation for Face Width Data, Exams of Biostatistics

Download Biostatistics Exam 2: Hypothesis Testing and Power Calculation for Face Width Data and more Exams Biostatistics in PDF only on Docsity! BIO 510/710 Biostatistics Frederick Fall 2001 Exam 2 Name: Directions: Answer each question thoroughly. Show all work and explain procedures for full credit. Point values are given for each question. You can earn as much as 110 out of 100 points. 1. The lower face width (skeletal bigonial diameter in centimeters) was measured for North American white girls at 5 and 6 years of age (7 in each age group) to test the hypothesis that faces of 6-year-old girls are wider than those of 5-year-olds. Observation 5-year-olds 6-year-olds 1 7.33 7.53 2 7.49 7.70 3 7.27 7.46 4 7.93 8.21 5 7.56 7.81 6 7.81 8.01 7 7.46 7.72 a) State the null and alternate hypotheses to be tested (5 points). b) Carry out the two-sample t-test with a significance level of 0.05, showing your work and clearly identifying the critical value. What do you conclude? (20 points) c) What was the power of the test you just performed in part b? Show your work! (15 point) d) Now test the same hypothesis you listed in part a, but use the Mann-Whitney test instead of the t-test. Show your work and clearly identify the critical value of the test statistic. What do you conclude now? (20 points)