Internal Validity
	To learn more about the book this website supports, please visit its Information Center. 2009 McGraw-Hill Higher Education Any use is subject to the Terms of Use and Privacy Policy. McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.

		Log In You must be a registered user to view the premium content in this website. If you already have a username and password, enter it below. If your textbook came with a card and this is your first visit to this site, you can use your registration code to register. Username: Password: Forgot your password?

		Site Preferences (Log out) Send mail as: TA email: Other email: "Floating" navigation? Drawer speed:

		Notes (What is this?)      Add a note 1. (optional) Enter a note here: 2. (optional) Select some text on the page (or do this before you open the "Notes" drawer). 3. Highlighter Color: NoneYellowRedGreenBlue 4.

		Search Search for: Search in: This siteThe web (PowerSearch)

Home > Chapter 9

Course-wide Content Guide to Electronic Re... Sample Statistics Sample Graphs Forms Glossary Bibliomaker SPSS Exercises Excel Exercises Research Applets Statistics Program Research Wizard Professional Journals

Choose a ChapterChapter 1Chapter 2Chapter 3Chapter 4Chapter 5Chapter 6Chapter 7Chapter 8Chapter 9Chapter 10Chapter 11Chapter 12Chapter 13Chapter 14Chapter 15Chapter 16Chapter 17Chapter 18Chapter 19Chapter 20Chapter 21Chapter 22Chapter 23Chapter 24Chapter 25

Chapter Outlines Chapter Objectives Main Points Key Terms Flashcards News, Articles & Links Web Links Quizzes Multiple Choice Quiz True or False Quiz Essay Quiz Interactive Exercises Research in Action More Resources Problem Sheets Learn More About... Voices of Teacher Rese... Interactive Activities

Instructor Resources Instructor's Manual Handout Masters PowerPoint Presentations Test Banks EZTests Activity Book Answer Key CPS by e-Instruction Course-wide Content Guide to Electronic Re... Sample Statistics Sample Graphs Forms Glossary Bibliomaker SPSS Exercises Excel Exercises Research Applets Statistics Program Research Wizard Professional Journals

Choose a ChapterChapter 1Chapter 2Chapter 3Chapter 4Chapter 5Chapter 6Chapter 7Chapter 8Chapter 9Chapter 10Chapter 11Chapter 12Chapter 13Chapter 14Chapter 15Chapter 16Chapter 17Chapter 18Chapter 19Chapter 20Chapter 21Chapter 22Chapter 23Chapter 24Chapter 25

Chapter Outlines Chapter Objectives Main Points Key Terms Flashcards News, Articles & Links Web Links Quizzes Multiple Choice Quiz True or False Quiz Essay Quiz Interactive Exercises Research in Action More Resources Problem Sheets Learn More About... Voices of Teacher Rese... Interactive Activities