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PSYCH202A: Research Methods

Unit 6: Understanding Research Results   *One of the most important aspects of the research process is understanding the results that your experiment yields. While this may seem like an easy (or obvious) task, there are a number of steps you should follow if you wish to accurately understand and use your results. This unit we will review the ways in which experimental results should be tested, interpreted, and understood.

Most of your results will likely be in the form of statistics. We will touch upon statistics in this unit, but you needn’t know how to calculate them. You need only understand what each statistic means and the concept (or concepts) to which it refers.*

Unit 6 Time Advisory
This unit should take approximately 11.5 hours to complete.

☐    Subunit 6.1: 3 hours

☐    Sub-subunit 6.1.1: 1 hour

☐    Sub-subunit 6.1.2: 2 hours

☐    Subunit 6.2: 6.5 hours

☐    Sub-subunit 6.2.1: 1 hour

☐    Sub-subunit 6.2.2: 0.5 hours

☐    Sub-subunit 6.2.3: 1 hour

☐    Sub-subunit 6.2.4: 0.5 hours

☐    Sub-subunit 6.2.5: 1.5 hours

☐    Sub-subunit 6.2.6: 1 hour

☐    Sub-subunit 6.2.7: 1 hour

☐    Subunit 6.3: 1 hour

☐    Subunit 6.4: 1 hour

Unit6 Learning Outcomes
Upon completion of this unit, the student will be able to: - Identify the purpose of descriptive statistics; define the three main types of descriptive statistics. - Define correlation and identify the strength and direction of the relationship between two variables. - Identify the appropriate inferential statistic for various research designs. - Identify the research situation for which a t-test would be appropriate and outline the procedure for conducting a t-test. - Identify the research situation for which a one-way analysis of variance (ANOVA) would be appropriate and outline the procedure for conducting a one-way ANOVA. - Identify the issues affecting the generalizability of the results of a study.

6.1 Descriptive Statistics and Correlation   6.1.1 Descriptive Statistics   - Reading: Research Methods Knowledge Base: William Trochim’s “Descriptive Statistics” Link: Research Methods Knowledge Base: William Trochim’s “Descriptive Statistics” (HTML)

 Instructions: Descriptive statistics are used to *describe* a set
of numbers, the first step in analyzing data. Please read this
webpage for a definition of descriptive statistics. At the end of
this reading, you should be able to identify the purpose of
descriptive statistics and to define the three main types of
descriptive statistics: frequency distribution, measures of central
tendency, and measures of dispersion.  

 Reading this webpage should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above. The Saylor Foundation is grateful to
Professor William Trochim for his kind permission to reference
students to this site.

6.1.2 Describing Relationships: Pearson Correlation Coefficient (r) and Regression Equations   - Reading: Cengage Learning’s Workshop: “Correlation” and AllPsych Online: Dr. Christopher L. Heffner’s “Chapter 8.6: The Correlation” Link: Cengage Learning’s Workshop: “Correlation” (HTML) and AllPsych Online: Dr. Christopher L. Heffner’s “Chapter 8.6: The Correlation” (HTML)

 Instructions: Correlations are used to describe the *strength* and
*direction* of the relationship between two variables. Please
complete all portions of the workshop, including the quiz at the
end, for a review of correlation and regression. Also, please read
webpage from AllPsych Online for an understanding of correlational
relationships and the correlation coefficient. After completing this
subunit, you should be able to define correlation and identify the
strength and direction of a correlation when presented with a
scatterplot of the data or when presented with a correlation
coefficient.  

 Completing this workshop and reading these webpages should take
approximately 2 hours (about 1 hour and 30 minutes for the workshop
and 30 minutes for the reading).  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpages above.

6.2 Statistical Inference   6.2.1 Selecting the Appropriate Statistical Test   - Assessment: Cengage Learning’s Workshop: “Choosing the Correct Statistical Test” Link: Cengage Learning’s Workshop: “Choosing the Correct Statistical Test” (HTML)

 Instructions: Inferential statistics are used to make *comparisons*
between groups. Please complete all portions of this workshop,
including the quiz at the end, to understand the process of choosing
the appropriate inferential statistical test for a given research
situation. At the end of this subunit, you should be able to
identify the statistical procedures used for scale data with
multiple samples and you should be able to describe the research
design for which each would be appropriate.  

 Completing this workshop should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.2.2 Statistical Significance   - Reading: Texas A&M; University: Bruce Thompson’s “The Concept of Statistical Significance Testing” Link: Texas A&M University: Bruce Thompson’s “The Concept of Statistical Significance Testing” (HTML)

 Instructions: Statistical significance is used to determine whether
or not findings are likely to be reliable. Please read this webpage
to understand the meaning of statistical significance. At the end of
this subunit, you should be able to define statistical
significance.  

 Reading this webpage should take approximately 30 minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on Bruce Thompson’s “The Concept of Statistical
Significance Testing.”

6.2.3 Sampling Distributions   - Assessment: Cengage Learning’s Workshop: “Sampling Distributions” Link: Cengage Learning’s Workshop: “Sampling Distributions” (HTML)

 Instructions: Sampling distributions are an important component in
making statistical decisions (especially in determining statistical
significance). Please complete all portions of this workshop,
including the quiz at the end, to gain an understanding of sampling
distributions.  

 Completing this workshop should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.2.4 The Null Hypothesis versus the Research Hypothesis   - Reading: Research Methods Knowledge Base: William Trochim’s “Hypotheses” Link: Research Methods Knowledge Base: William Trochim’s “Hypotheses” (HTML)

 Instructions: Please read this webpage for a review of null and
alternative hypotheses. At the end of this subunit, you should be
able to define the null and alternative hypothesis and identify
their role in statistical hypothesis testing.  

 Reading this webpage should take approximately 30 minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above. The Saylor Foundation is grateful to
Professor William Trochim for his kind permission to reference
students to this site.

6.2.5 Errors: Type I Error and Type II Error; Statistical Power   - Assessment: Cengage Learning’s Workshop: “Statistical Power” Link: Cengage Learning’s Workshop: “Statistical Power” (HTML)

 Instructions: Please complete all sections of this workshop,
including the quiz at the end, to learn about the types of error and
their relationship to statistical power. At the end of this subunit,
you should be able to define Type I error, Type II error, and
statistical power.  

 Completing this workshop should take approximately 1 hour and 30
minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.2.6 The t-Test and What It Tells Us About Our Results   - Reading: Research Methods Knowledge Base: William Trochim’s “The T-Test” Link: Research Methods Knowledge Base: William Trochim’s “The T-Test” (HTML)

 Instructions: The t-test is used to compare the means of two
groups. Please read this webpage for an introduction to the
interpretation of t-tests. At the end of this subunit, you should be
able to identify the research situation for which a t-test would be
appropriate and outline the procedure for carrying out a t-test.  

 Reading this webpage should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above. The Saylor Foundation is grateful to
Professor William Trochim for his kind permission to reference
students to this site.

6.2.7 The F-Test and What It Tells Us About Our Results   - Reading: Psychology World: Richard Hall’s “Between Subjects One-Way ANOVA Description” Link: Psychology World: Richard Hall’s “Between Subjects One-Way ANOVA Description” (HTML)

 Instructions: Please read this webpage to identify the research
situation for which an F-test would be appropriate and outline the
procedure for carrying out a one-way analysis of variance (ANOVA).
You should also be able to describe the relationship between the
t-test and F-test, including a description of the research
situations for which each would be most appropriate.  

 Reading this webpage should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.3 Generalization of Results   - Reading: Hanover College: Dr. William Altermatt’s “External Validity” Link: Hanover College: Dr. William Altermatt’s “External Validity” (PDF)

 Instructions: After you click on this link, you will see a number
of readings. Please click on “External Validity” in order to
download the PDF for an explanation of external validity and how to
generalize results. At the end of this subunit, you should be able
to identify the issues affecting the generalizability of the results
of a study.  

 Reading this webpage should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.4 Assessment: Statistical Inference   - Reading: McGraw-Hill: Paul C. Cozby’s “Multiple-Choice Test on Understanding Results: Statistical Inference” Link: McGraw-Hill: Paul C. Cozby’s “Multiple-Choice Test on Understanding Results: Statistical Inference” (HTML)

 Instructions: After you have completed Unit 6, please take the
above assessment to test your knowledge. Note that some of the items
may refer to specific material that was not covered in this section.
You may use those items to determine how well your knowledge will
generalize to other aspects of statistical inference.  

 Completing this assessment should take approximately 1 hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.