copyright © allyn & bacon (2010) selecting statistical procedures graziano and raulin research...

Copyright © Allyn & Bacon (2010)Copyright © Allyn & Bacon (2010)

Selecting Statistical Selecting Statistical ProceduresProcedures

Graziano and RaulinGraziano and RaulinResearch Methods: Appendix DResearch Methods: Appendix DThis multimedia product and its contents are protected under copyright law. The following are This multimedia product and its contents are protected under copyright law. The following are prohibited by law: (1) Any public performance or display, including transmission of any image prohibited by law: (1) Any public performance or display, including transmission of any image over a network; (2) Preparation of any derivative work, including the extraction, in whole or in over a network; (2) Preparation of any derivative work, including the extraction, in whole or in part, of any images; (3) Any rental, lease, or lending of the program.part, of any images; (3) Any rental, lease, or lending of the program.


Selecting Statistical Selecting Statistical ProceduresProcedures Selecting statistical analysis Selecting statistical analysis

procedures is part of the design procedures is part of the design processprocess

Based on the characteristics of the Based on the characteristics of the studystudy

Use the information about the study to Use the information about the study to follow the flowchart to arrive at follow the flowchart to arrive at decisions about statistics to usedecisions about statistics to use

Need not memorize the flowchartNeed not memorize the flowchart


Describing Your Describing Your ResearchResearch1.1. What is its level of constraint, What is its level of constraint,

dependent variables, and level of dependent variables, and level of measurement of each dependent measurement of each dependent variable?variable?

2.2. What are the independent variables, What are the independent variables, what type (between-subjects or within-what type (between-subjects or within-subjects), and how many levels?subjects), and how many levels?

3.3. What is (are) the research hypothesis What is (are) the research hypothesis (hypotheses)?(hypotheses)?


Flowchart StructureFlowchart Structure

Descriptive Statistics (up and right)Descriptive Statistics (up and right)– These should always be doneThese should always be done

Other statistics (down the left side)Other statistics (down the left side)– Manipulation check (if relevant)Manipulation check (if relevant)– CorrelationsCorrelations

Relevant if it is correlational researchRelevant if it is correlational research Often included in higher constraint research to Often included in higher constraint research to

identify potential confounding variablesidentify potential confounding variables

– Testing Mean DifferencesTesting Mean Differences The most common inferential statistical procedureThe most common inferential statistical procedure


Functional FlowchartFunctional Flowchart(Student Resource Website)(Student Resource Website)

Functional Functional flowchart walks you flowchart walks you through the through the process of selecting process of selecting a statistical testa statistical test

Links to the manual Links to the manual and computerized and computerized computation computation tutorialstutorials


Secondary AnalysesSecondary Analyses

Defined as analyses that do not directly Defined as analyses that do not directly test the hypothesis of the studytest the hypothesis of the study

Three types of secondary analysesThree types of secondary analyses– Post hoc analysesPost hoc analyses: Such as specific : Such as specific

means comparisons in ANOVAmeans comparisons in ANOVA– Secondary analyses to explain resultsSecondary analyses to explain results– Data snoopingData snooping: Exploring the data for : Exploring the data for

clues that might form hypotheses for later clues that might form hypotheses for later researchresearch


Caveats and Caveats and DisclaimersDisclaimers Flowchart is a teaching device onlyFlowchart is a teaching device only NOT every statistical procedure is NOT every statistical procedure is

includedincluded– Only the most common (e.g., testing mean Only the most common (e.g., testing mean

differences)differences) Procedures suggested by flowchart, Procedures suggested by flowchart,

although the correct procedures to although the correct procedures to use, are NOT the only correct use, are NOT the only correct procedures for that situationprocedures for that situation


Robust Statistical Robust Statistical ProceduresProcedures A statistical procedure is robust to an A statistical procedure is robust to an

assumption IF the assumption can be assumption IF the assumption can be violated without distorting resultsviolated without distorting results

Evaluated with Monte Carlo proceduresEvaluated with Monte Carlo procedures– Computer simulations of the effects of various Computer simulations of the effects of various

situations on the effectiveness of a statisticsituations on the effectiveness of a statistic Evidence suggests that assumption Evidence suggests that assumption

violations have little effect violations have little effect IFIF your sample your sample sizes about equal in each groupsizes about equal in each group


SummarySummary

Select statistical procedure as part of Select statistical procedure as part of design processdesign process– Statistical procedures selected before data Statistical procedures selected before data

collectioncollection– Selection based on study characteristicsSelection based on study characteristics– Functional version of the flowchart is on Functional version of the flowchart is on

the website, with links to how to compute the website, with links to how to compute each statistical procedureeach statistical procedure

copyright © allyn & bacon (2010) selecting statistical procedures graziano and raulin research...

Documents