ANCOVA

As you have learned this week, ANCOVA can be a valuable tool in research design. For this Application, you will use ANCOVA to analyze data from a research study.
To prepare for this Application:

  • Review Chapter 12 of the Field text for a description of the analysis of covariance and an example of conducting an analysis of covariance using PASW.
  • Review Chapter 5 from the APA manual, “Displaying Results.”
  • Review the media about conducting an ANCOVA.
  • Read the research study below.

RESEARCH STUDY:
Stalking is a very disruptive and upsetting experience in which someone (the stalker) constantly harasses or obsesses about another person. Stalking can take many forms, from sending intensely disturbing letters to literally following you around in the places where you live and socialize. A psychologist decides to try two different therapies on people who reported a history of stalking and reported currently exhibiting stalking behaviors (25 stalkers in each group; this is the Group variable in the data set Stalker.sav). With those in group one, the psychologist used a cognitive-behavioral approach. With those in the second group, she used a psychodynamic approach. At the end of 3 months, the psychologist asked the clients to report on the number of hours each week they engaged in stalking-type behaviors (this variable is called Stalk2 in the data set). The psychologist understands about covariance and believes that success of the therapy will likely depend on how bad the behavior was to begin with, so she asked the clients to report at their first session the number of hours that the client engaged in stalking-type behaviors (this variable is called Stalk1 in the data set).
The assignment:
Following the example in the text outlined on pp. 490–493, analyze the effect of the therapies on stalking-type behaviors after therapy ended while controlling for initial number of hours of stalking-type behaviors.
Report your findings in APA format according to the guidelines in the PASW Application Assignment Guidelines handout. The final document should be 2–3 pages long.
Anthony Napoli WALDEN INSTRUCTOR MANAGER
Week 5 Discusion Board – ANCOVA: Important
COLLAPSE
 
 
Here’s what you need to do for the Week 5 application assignment – ANCOVA
I)
a- Read chapter 12 in the Andy Field textbook.  Take notes on the chapter, and ask questions on any parts of or concepts  within the chapter that you do not FULLY understand.
b- Read all of my posts in this discussion board – ASK QUESTIONS.
c-View and read the instructional Videos and Notes in the Week 5 Resources Pages – ASK QUESTIONS.
II)
1) Write a Null and Alternative Hypothesis specific to the research questions.
2) Explain the assumptions of ANCOVA and test the assumptions of ANCOVA (hint, Levene’s test for the between group factor, and homogeneity of regression for the CV and DV) – report the results of these test to determine of the data met the assumptions in correct APA format.
3) Report the group sample sizes and type of statistical analysis, also report means, 95% CI for means, SDs, SE, adjusted means.  Plot the adjusted means.
4) Report and interpret the F-ratio, the p-value for F, and the effect size.
5) Report the type of post hoc test conducted and the results from the post hoc test
6) What conclusions can be drawn fro the study?
7) Create APA formatted tables for the means and the ANCOVA.
8) Attach the SPSS syntax and output.
It is required that you read my sample summary, posts, the assigned Field text chapter, and the Resource Notes within the Week 5 Discussion Board above.
Required Resources

  • Course Text: Discovering Statistics Using IBM SPSS Statistics
    • Chapter 12, “Analysis of Covariance, ANCOVA (GLM 2)”
      In this chapter, you will learn about assumptions and issues in ANCOVA, conducting ANCOVA on SPSS, interpreting the output of ANCOVA, and ANCOVA as a multiple regression.
  • Website: Trochim, W.M.K. (2006). Covariance designs. Retrieved from http://www.socialresearchmethods.net/kb/expcov.php
    This website provides a description of covariance and explains its functions.
  • Handout: Statistics Application Evaluation Criteria (Word document)
    This handout will guide you in completing and submitting your ANCOVA Application Assignment for this week.
  • Software: IBM SPSS Statistics Standard GradPack (current version). Available in Windows and Macintosh versions. Please refer to the IBM SPSS Software area on the left navigation bar for more information on how to install, register, and license this software.
    You will use this software to complete this week’s Application Assignment.

Media

  • Analysis of Covariance — Conceptual (Adobe Captivate)
    Dr. Jennifer Morrow explains the conceptual framework of an analysis of covariance. This Flash-based demonstration will open in a new window.
    (Transcript for Analysis of Covariance — Conceptual)
  • Analysis of Covariance — Applied (Adobe Captivate)
    Dr. Jennifer Morrow provides an example of the analysis of covariance using PASW. This Flash-based demonstration will open in a new window.
    (Transcript for Analysis of Covariance — Applied)

Research Toolkit
 
Research Design

  • Website: Web Center for Social Research Methods
    http://www.socialresearchmethods.net
    This website is for people involved in applied social research and evaluation. You will find several resources and links to other locations on the web that deal in applied social research methods.
  • Website: Cengage Research Methods Workshops
    http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/resch_wrk.html
    This website offers many useful workshop topics such as experimental methods, reliability and validity, surveys, sampling methods, ethical issues, and evaluating published research.

Statistics and SPSS

  • Website: SPSS Solutions for Education: Student Resources
    http://www-01.ibm.com/software/analytics/spss/academic/students/resources.html
    The SPSS student support site provides a knowledgebase and allows students to request assistance from SPSS Technical Support staff. Since this site is produced and maintained by the creators of the PASW software, it is the best place to go when you have a question about the software.
  • Website: UCLA’s ‘What Statistical Analysis Should I Use?’ Table
    http://www.ats.ucla.edu/stat/mult_pkg/whatstat/default.htm
    This statistics table shows general guidelines for choosing a statistical analysis, and links showing how to do such tests using SAS, Stata and PASW. This is a good place to go if you are not sure which statistical test would best answer the research question you have.
  • Website: Cengage Statistics Workshops
    http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/stats_wrk.html
    This website offers many useful workshop topics such as experimental methods, ethical issues, and evaluating published research.

Optional Resources

  • Text: Using Multivariate Statistics
    • Chapter 6, “Analysis of Covariance”
      This text offers another explanation of the analysis of covariance and goes into more depth regarding the statistical background of the test.
  • Text: Publication Manual of the American Psychological Association
    • Chapter 5, “Displaying Results”
  • Website: Research Methods Knowledge Base
    http://www.socialresearchmethods.net/kb/statcov.php

Media

  • Data Cleaning and Dealing with Assumptions (Adobe Captivate)
    Dr. Jennifer Morrow explains the assumptions surrounding many of the tests you will study and explains ways that you can manage data that violates these assumptions. This Flash-based demonstration will open in a new window.
 
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