SUMMARY

• Hypothesis


  An explanation of a relationship between two or more variables. Thesis, or main idea of an experiment. Statement about a predicted relationship of at least two variables.
• Experimental hypothesis


  A tentative explanation of an event or a behavior. A statement that predicts the effect of an independent variable on a dependent variable.
• Experimental hypothesis


  • Cognitive behavior therapy (CBT) produces less relapse than antidepressants.
• Nonexperimental hypothesis


  Predicts how variables (events, traits, or behaviors) might be correlated, but not causally related.
• Nonexperimental hypothesis


  • Red-haired patients receive less relief from pain medication than blonde patients.
• Synthetic statements


  Statements that could either be true or false. Can be supported or contradicted.
• Synthetic statement


  • Hungry students read slowly.
• A hypothesis must be capable of being true or false.
• Nonsynthetic statements


  Two categories: (1) analytic or (2) contradictory
• Analytic statement


  A statement that is always true.
• Analytic statement

  • The weight of the dieters will fluctuate.
• Contradictory statement


  A statement that is always false. Statements with elements that oppose each other.
• Contradictory statement


  • I have a brother and I do not have a brother.
• Testability


  An experimental hypothesis is testable when it can be assessed by manipulating an IV and measuring the results on the DV.
• Without testability, we cannot evaluate the validity of a hypothesis.
• Parsimony


  A simple hypothesis over one requiring many supporting assumptions. A simple hypothesis allows us to focus our attention on the main factors that influence our dependent variable.
• Fruitful


  A hypothesis must be fruitful, it leads to new studies.
• Falsifiable


  A research hypothesis must be falsifiable (disprovable) by research findings.
• Hypotheses need to be worded so that failures to find the predicted effect must be considered evidence that the hypothesis is indeed false.
• Induction


  Reasoning from specific cases to general principles to form a hypothesis. Used in forming a hypothesis.
• Researchers use inductive reasoning to construct theories by creating explanations that account for empirical data (observations).
• Scientists can use the results of extensive experiments designed to test hypotheses to construct a theory that unifies their findings.
• Deduction


  Reasoning from general principles to specific predictions. This approach is used to test the assumptions of a theory.
• Equity theory


  Formulated by Walster et al. Combination of induction and deduction. Based on specific observations (induction) and then tested predictions from this theory (deduction).
• The most useful way to develop a hypothesis is to review research that has already been published. Both experimental and nonexperimental studies can prove helpful.
• Ways a review of prior experiments helps

  • Identifies questions that have not been conclusively answered or addressed at all
  • Suggests new hypotheses
  • Identifies additional variables that could mediate an effect
  • Identifies problems other researchers have experienced
  • Helps avoid duplication of prior research when replication is not intended
• Serendipity


  A scientist who is open to unexpected results and who is sufficiently informed can understand the significance of unexpected findings.
• Intuition


  Knowing without reasoning, or unconscious problem-solving. Guides what we choose to study in an experiment.
• Our intuition must be supported by our literature review.
• Three promising strategies in developing an experimental hypothesis

  • Read an issue of a psychology journal
  • Observe how people behave in public places
  • Choose a real-world problem and try to identify its cause
• Introduction section


  Provides a selective review of research findings related to the research hypothesis. Identifies which questions have not been definitively answered by previous studies and helps show how your experiment advances knowledge in this area.
• Meta-analysis


  Measures the average effect size of an independent variable across studies that share similar methodologies. This statistical procedure helps establish the strength and external validity of a causal relationship.
• A meta-analysis is not an experiment, but rather a statistical analysis of many similar studies.
• Independent variable (IV)


  The variable (antecedent condition) an experimenter intentionally manipulates.
• Levels of an independent variable


  The values of the IV created by the experimenter.
• An experiment requires at least two levels of the independent variable.
• Confounded experiment


  When the value of an extraneous variable systematically changes along with the independent variable.
• Confounded experiment


  • Running experimental subjects in the morning and control subjects at night.
• Dependent variable


  The outcome measure the experimenter uses to assess the change in behavior produced by the independent variable.
• Operational definition


  Specifies the exact meaning of a variable in an experiment by defining it in terms of observable operations, procedures, and measurements.