Research Methods With Statistics 8-10% of AP Exam PSYCHOLOGY IS A SCIENCE!!!
Broad Categories of Research Methods Descriptive Correlational Experimental
Comparing Research Methods Basic Purpose How conducted What is manipulated Descriptive To observe and record behavior Case studies, surveys, naturalistic observation Nothing is “changed” Examples?
Comparing Research Methods Basic Purpose How conducted What is manipulated Correlational To detect naturally occurring relationships (assess how well does one variable predict another) Computing statistical associations Nothing is manipulated Examples?
Comparing Research Methods Basic Purpose How conducted What is manipulated Experimental To explore cause and effect Manipulate one or more factors (variables) Use random assignment Eliminate preexisting conditions The independent variable(s) Examples?
A Closer Look at Experiment Design
Experimental Design-only method meant to show “cause and effect” Hypothesis- A statement about the relation between two or more variables Must be testable, verifiable and refutable Null Hypothesis- a formal expression that there is NO relation between or among the variables under investigation One attempts to reject the null when a relationship is observed
Experimental Variables Independent- variable manipulated by the experimenter (IV) Dependent- Measured variable influenced by the independent variable (DV) Confounding- any variable besides the IV that could influence the experimental results (this is unwanted)
Subject Groups Experimental Group Control Group The group that receives treatment (IV) Control Group Group that does not receive treatment (or receives treatment that is presumed to be ineffective e.g. placebo) Used as a basis of comparison Serves to eliminate alternative explanations of the results
Population Sample Representative The larger group of people or animals from which the sample is drawn Sample-set of subjects drawn from a particular population Representative Sample- selected subjects are reflective of the population from which the sample is drawn Sample Representative
Control Measures Counterbalancing- Randomization- Controls for order effect of conditions Randomization- Selection and assignment of subjects to groups through chance procedure
Control Measures Single-blind- Double-blind- Controls subject awareness of group assignment Double-blind- Controls subject and experimenter awareness of group assignment
Operational Definition- an empirical measure of a vague term
Other Research Methods
Ex Post Facto Method- Latin for “after the fact” Subjects selected based on conditions already present Independent Variable (IV) established or manipulated by nature Cannot make cause and effect statements about results Most often used due to ethical concerns
Other Research Methods Naturalistic Observations Behavior observed or “watched” in a natural setting Typically, behavior is not interfered with or altered
Other Research Methods Case Studies An intensive (often long-term) study of an individual or small group of individuals In-depth information but may not always applicable to larger sample
Other Research Methods Surveys Methods used to measure attitudes, motives, opinions and such Self report data: interpreted cautiously Easily biased Small rate of returns Phrasing of questions may affect respondents’ answers
Other Research Methods Correlational Method – this is meant to show relationship among variables Variables are quantified and statistically compared Shows strength of relationship Helps in study when experiment would be unethical (abuse, violence, unhealthy living styles) Strength of relationship is shown by absolute value of correlation coefficient (more about this later) Cheap/easy However. . .
CORRELATION DOES NOT IMPLY CAUSATION!!!! This is important to note. There is often an AP question regarding this concept.
READ ALL ABOUT IT SEE HANDOUT (last week) ETHICS- ethical guidelines are established by the American Psychological Association (APA) READ ALL ABOUT IT SEE HANDOUT (last week)