Ch. 4 - Research Design Fundamentals Flashcards
Variable
-Is any event, situation, behaviour, or individual characteristic that can take more than one value (ie. it varies)
What are the 2 basic research designs?
- Non-experimental method
2. Experimental method
Non-experimental method
- With this method, relationships are studied by observing or otherwise measuring the variable of interest
- Important point: BOTH variables are measured when using the non-experimental method
- Using this approach may include asking people to describe their behaviour, directly observing behaviour, recording physiological responses, or examining various public records such as census data
- This method does not help us answer questions about cause and effect
Experimental method
- Involves direct manipulation and control of variables. The researcher manipulates the first variable of interest and then observes the response
- One variable is introduced first to see whether it affects the second variable
Operational definition
-Definition of a concept that specifies the operation used to measure or manipulate the concept
What are the 3 general categories to think of variables?
- Situational variable
- Response variable
- Participant variable
Situational variable
- Describes characteristics of a situation or environment
- Ex. the length of words that you read in a book, the number of people who are squeezed into a classroom, the credibility of a person trying to persuade you, and the number of bystanders to an emergency
-Situational variables can be measured in any design, or manipulated in experimental designs
Response variable
- Operational definitions that involve recording a participant’s reaction to some event
- Ex. reaction time, performance on a cognitive task, and degree of helping a victim in an emergency
- Response variables are measured in either experimental or non-experimental designs
Participant variable
- Describes a characteristic that individuals bring with them to a study
- Ex. cultural background, intelligence, and personality traits such as extroversion
- It is often treated as an independent variable in experimental designs, despite the lack of random assignment
Confounding variables
- Confounds are variables that are intertwined with another variable so that you cannot determine which of the variables is operating in a given situation
- Confounds can result from imprecise operational definitions
4 types of relationships between variables
- Positive linear relationship = both variables increase OR both variables decrease (ie. same direction)
- Negative linear relationship = increases in one variable causes decreases in the other OR decreases in one variable causes increases in the other (ie. opposite directions)
- Curvilinear relationship = both variables increase together, then decrease together (or vice versa) (ie. direction changes at least once). Also called an INVERTED-U RELATIONSHIP
- No relationship = flat line on graph. As one variable changes, the other does not change in any systematic way
Correlation coefficient
-Is the numerical index of the strength of relationship between variables
Mediating variable
- Is a psychological process that occurs between two variables that helps explain the relationship
- A psychological process that occurs between an event and a behavioural response
What are the 2 main problems preventing researchers from making causal statements when the non-experimental method is used?
- It can be difficult to determine the direction of cause and effect
- The THIRD-VARIABLE problem - that is, extraneous variables may be causing an observed relationship
Third-variable problem
-When describing the relationship between two variables, a third variable is any other variable that is extraneous to the 2 variables of interest