LAPD FINAL EXAM STUDY GUIDE – Fall 2009
Goals of Psychological Science:
* Description of behavior and the mind
Relies on identifying reliable patterns in behavior or thought. This provides material for later efforts to explain and predict psychological events.
* Prediction of behavior and thought
Using psychological descriptions to acknowledge reliable relationships between variables.
* Explanation of formulation of models of the mind
Specification of why certain relationships are observed and predicted between variables (that is, a theory is developed to account for the relationship).
* Application of these models for influencing behavior and thought.
Using ...view middle of the document...
Induction vs. Deduction
Deduction: Theory Data
Use a general theory to make predictions about a specific situation.
Induction: Data Theory
A researcher notices a phenomenon of interest and generalizes from those pieces of data to a theory that makes predictions in other situations.
* Operational definitions: operational definition of our variables - a clear and precise explanation of the items being measured.
- E.g., test performance
* Hypothesis was testable - it clearly states what must be manipulated and measured.
* Our experiment is reliable - it can be replicated easily and will yield the same pattern of results.
Experimental Variables (4 types):
What is a variable?
* A variable is an entity that is controlled, changed, or manipulated or measured by an experimenter.
* Can be qualitative (categorical; sex or classification) or quantitative (e.g., age or reaction time).
* Qualitative data are binned into distinct groups.
* Cannot assume continuity between bins
* Quantitative data occur on a continuous distribution
* 1. Independent variables are variables which are manipulated by the experimenter to produce some effect.
* 2. Dependent variables are variables which are measured by the experimenter and taken to represent the degree to which some effect exists.
* 3. Control variables are held constant across all levels of the IV in an experiment and allow us to measure only the effect of the IV on the DV.
* 4. Confounding variables are variables which influence the dependent variable separate from the IV. These are bad.
Types of Validity (5 types)
o Threats to types of validity
1) Internal Validity:
When the results can be attributed with little or no ambiguity to the effects of the independent variable, the experiment is said to be internally valid
THREATS to Internal Validity:
- History: refers to any event other than the IV that may account for the results. Events in the participants lives can affect the DV (at home, school or work)
-Maturation: some variables which affect the results over time( long term: growing older, wiser, stronger; short term: becoming distracted, bored or tired)
-Testing: the effects of taking a test once on subsequent performance
Instrumentation: effects of changing measuring instruments or procedures (not controlling for task order, having different experimenters, etc)
Selection biases: systematic differences between groups before manipulation of the IV
Attrition: loss of subjects in experiments that require more than one measurement
2) External Validity: refers to the extent to which the results of an investigation can be generalized beyond the conditions of the experiment to other populations, settings and circumstances
THREATS to External Validity
-Sample characteristics: refers to the potential difficulty of generalizing results beyond the subjects’...