EXPEPSY FINALS REVIEWER

• Design


  Details an experimenter's plan for testing a hypothesis
• Experimental Design


  Largely determined by experimental hypothesis
• Factors that mainly determine the selection of an experimental design

  • The number of independent variables in the hypothesis
  • The number of treatment conditions needed to test the hypothesis fairly
  • Whether the same subjects are used in each of the treatment conditions
• Between-Subjects Design


  Randomly assign different subjects to each treatment condition
• Within-Subjects Design


  Same subjects participate in more than 1 treatment condition
• Between-Subjects Designs


  • Two-Groups Designs
  • Two Matched Groups Designs
  • Multiple-Groups Designs
• Two-Group Designs


  There is one IV with 2 levels and subjects are randomly assigned
• Random Assignment


  Assigning subjects to conditions so that each subject has an equal chance of participating in each condition
• Experimental Condition


  Presents a value of the independent variable
• Control Condition


  Presents a zero level of the independent variable
• Two Independent Groups Designs

  • Experimental Group-Control Group Design
  • Two Experimental Groups Design
• Effectiveness of Randomly Assigning Subjects to Different Conditions

  • Random assignment works poorly with 5-10 subjects per condition
  • We should have at least 20 subjects in each treatment condition unless the treatment effect is enormous
• Two-Matched Group Design


  Measures and matched pairs of subjects on different factors and then randomly assigns the matched pairs to treatment conditions
• Methods to match pairs of subjects

  • Precision-Making
  • Range Making
  • Rank-Ordered Making
• Matching


  Used to create groups that are equivalent to potentially confounding subject variables
• Successful matching prevents selection threats from undermining interval validity
• We need to measure an extraneous variable, strongly correlated with the dependent variable, that could confound our results if not controlled
• When to use a two-matched groups design


  When there are two levels of an independent variable, and there is an extraneous variable we can measure that could affect the dependent variable
• Multiple Groups


  A between-subjects design with more than 2 levels of an independent variable
• Block Randomization


  Process for randomly assigning equal numbers of subjects to conditions
• The hypothesis, prior research, pilot study results, and practical limits can all help determine the number of treatments
• Research Report


  Major part of the research process, divided into several important sections: Introduction, Method, Results, Discussion, (Abstract & List of References)
• Purpose of a Research Report

  Primary purpose is communication of research findings, written in scientific writing style (informative, not entertaining), must be concise, due to limited space, and unbiased
• APA formatting


  Psychological Reports are expected to follow APA formatting, current standard is the 7th Edition of the Publication Manual of the APA (2019)
• Title


  Give readers a description of what the report is all about, include both the IV and DV, and their RS in the title, be specific and concise (12 words or fewer)
• Abstract


  Summary of the report, usually between 150-250 words, includes a concise synopsis of the experiment, statement of the problem studied, participants involved, method, results, and major conclusions
• Introduction


  Sets the stage for the research that follows, includes hypothesis statements, evidence as to why the research is important, literature review with citations to background experiments
• Method


  Tells how the experiment was performed and describes the participants, procedure, and materials, offers sufficient detail to allow readers to reasonably replicate the work, includes several major subsections: Participants, Measures, Manipulations, Design
• Results Section


  Describes the statistical procedures used to evaluate data and all obtained statistical values (df, significance levels), sometimes results can easily be summarized in tables, includes all group means, measures of variability, estimated effect sizes, and confidence intervals
• Discussion


  Evaluates the experiment, interprets the results, and brings the project full circle, explains and qualifies the findings, re-examines the initial hypotheses, identifies possible confounds and problems, suggests future ideas and possible studies
• Reference Section


  Lists all resources mentioned in the manuscript, enables readers to do their own background research and qualify what was done, APA guidelines for references are very specific
• Statistics


  Quantitative measurements of samples, concerned with developing and studying methods for collecting, analyzing, interpreting, and presenting empirical data
• Descriptive Statistics


  Describe sample central tendency and variability
• Inferential Statistics


  Allow us to conclude a parent population from a sample
• Population


  Set of people, animals, or objects that share at least one characteristic in common
• Sample


  Subset of the population that we use to draw inferences about the population
• Variability


  Fluctuation in a set of scores, there is no variability when all scores are identical, variability increases as scores differ more from each other
• Null Hypothesis (H0)


  Statement that the scores came from the same population and the independent variable did not significantly affect the dependent variable
• Alternative Hypothesis (H)


  Statement that the scores came from different populations and the IV significantly affected the DV
• Statistical Significance


  Results are statistically significant when the difference between treatment groups exceeds the normal variability of scores on the DV