Research Methods

• Hindsight Bias


  The tendency to believe, after learning an outcome, that one would have foreseen it

  
• Double Blind Procedure

  An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies

  
• Independent Variable


  The experimental factor that is manipulated--the variable whose effect is being studied

  
• Dependent Variables


  The outcome factor -- the variable that may change in response to manipulations of the independent variable

  
• Mode

  The most frequently occurring score(s) in a distribution

  
• Mean


  The arithmetic average of a distribution, obtaining by adding the scores and then dividing by the number of scores

  
• Median


  The middle score in a distribution--half the scores are above it and half are below it

  
• Standard Deviations


  A computed measure of how much scores vary around the mean score

  
• Random Assignment


  Assigning participants to experimental and control conditions by chance ,thus minimizing preexisting differences between those assigned to the different groups

  
• Random Sampling


  A sample that fairly represents a population because each member has an equal chance of inclusion

  
• Scatter plot


  A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation

  
• Illusory Correlation


  The perception of a relationship where none exists

  
• Case Study


  An observation technique in which one person is studied in depth in the hope of revealing universal principles

  
• Survey


  A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them

  
• Naturalistic Observation


  Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

  
• Correlation


  A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +1

  
• Experiment


  A research method in which an investigator manipulates one or more factors (independent variables) to observe the effects on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant variable

  
• Replication


  Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

  
• Statistical Significance


  A statistical statement of how likely it is that an obtained result occurred by chance

  
• Operational Definition


  A statement of the procedures used to define research variables. Ex human intelligence -- what an intelligence test measures.

  
• Critical Thinking


  thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.
• Theory


  an explanation using an integrated set of principles that organizes and predicts observations

  
• Hypothesis


  a testable prediction, often implied by a theory

  
• Population


  all the cases in a group, from which samples may be drawn for a study

  
• Sample


  items selected at random from a population and used to test hypotheses about the population
• Correlation Coefficient


  a statistical index of the relationship between two things (from -1 to +1)

  
• Placebo


  experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.

  
• Placebo Effect


  any effect that seems to be a consequence of administering a placebo

  
• Experimental Group


  in an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.

  
• Control Group


  in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

  
• Confounding Variable


  a factor other than the independent variable that might produce an effect in an experiment.

  
• Range


  the difference between the highest and lowest scores in a distribution

  
• Normal Curve/distribution


  a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (68% fall within one standard deviation of it) and fewer near the extremes

  
• Inferential Statistics


  numerical methods used to determine whether research data support a hypothesis or whether results were due to chance

  
• Informed Consent


  an ethical principle requiring that research participants be told enough to enable them to choose whether they wish to participate

  
• Debriefing


  the post-experimental explanation of a study, including its purpose and any deceptions, to its participants

  
• longitudinal study


  researchers follow the same subjects over an extended period of time.

  
• confirmation bias


  experimenter might consciously or unconsciously look to confirm what they already believe about their hypothesis
• Null hypothesis


  Researchers work to reject, nullify or disprove the null hypothesis. Researchers come up with an alternate hypothesis, one that they think explains a phenomenon, and then work to reject the null hypothesis.
• confidentiality


  researchers may not release or publish the names of anyone participating in the experiment.