Hw6.sol - AMS 7 Biostatistics Week 7 Homework Solutions Chapter 7(Glover Mitchell 1 Big decrease in phosphate levels due to new laws 2 2 2 2 First

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
AMS 7, Biostatistics Week 7 Homework Solutions 1. Big decrease in phosphate levels due to new laws? First determine if the variances are equal: H 0 : σ 2 2 = σ 2 1 , and H a : σ 2 1 6 = σ 2 1 . The F -statistic s 2 2 /s 2 1 = 2 . 7. Using the F - distribution with v 1 = 11 and v 2 = 9 degrees of freedom gives the critical value F 0 . 975 = 3 . 96 leading the conclusion that there is not enough evidence to reject H 0 . So, treat the variances as equal ( σ 2 2 = σ 2 1 ) when testing the two-sample hypothesis for the means: H 0 : μ 1 μ 2 , and H 0 : μ 1 > μ 2 . Calculate s 2 p = 1238 . 4 and test statistic t = 9 . 78, and use a t -distribution with 20 degrees of freedom and obtain a critical value of t 0 . 95 = 1 . 725 and thus reject H 0 . 3. Paired data for antibiotic eFects. Subtract the amoxicillin column from the penicillin column and get ( n d = 6) di±erences d = 6 , - 10 , 4 , 5 , - 7 , - 2 and calculate ¯ X d = - 2 , ¯ s 2 d = 4 . 12. Test H 0 = μ d
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/31/2010 for the course AMS 7 taught by Professor Prado,r during the Winter '08 term at University of California, Santa Cruz.

Ask a homework question - tutors are online