PSYC 2250 Lecture Notes - Lecture 4: Field Experiment, Confounding, Artificiality
26 Jun 2018
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PSYC 2250 Introduction to Psychological Research
Chapter 4 Studying Behavior
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Variable: something can vary (e.g. GPA, gender, self-esteem…)
- Levels or values (what the variable varies on can be either quantitative; number or
categories)
- 4 types of variables:
1. Situational variable
Aspects of the situation or environment
E.g. temperature in a room, length of words that you read a book
2. Response variable
E.g. how people sweat in a crowded room, reaction time, performance on a
cognitive task
3. Participant variable
Characteristics of individuals that they bring with them to a study e.g. gender,
age, personality, traits, etc
4. Mediating variable
A variable that occurs between situational variable and a response variable
E.g. helping is less likely when there are bystanders to an emergency
Operational Definitions of variables
Operational definition: a definition of the variable in terms of the operational or techniques the
researcher uses to measure or manipulate it.
Defining helps us communicate our ideas to others
Non-experiment and experimental methods overview
1. Non experimental method
- Relationships are studied by observing or otherwise measuring the variables of interest.
- E.g. asking people to describe their behavior, directly observing behavior, recording
physiological responses…..
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PSYC 2250 Introduction to Psychological Research
- Correlational method
- Collect data on to or more variable to examine the relationship to see how they
correlate
- When both variables on a numeric scale, 4 basic “shape” (relationship)
a) Positive linear
Scores on both variables tend to increase together
The more hours you study, the higher GPA
b) Negative linear
Scores on one decrease the other increase
Relationship quality increase, depression decrease
c) Curvilinear
Increase on one have both increase and decrease on the other
Independence (like a U shape) vs age??
d) No relationship
No pattern of dots and a flat line
E.g. price of cheese and number of stop signs
- Also necessary to now the strength of the relationship
-Correlation coefficient : size of the correlation between the variables
Strong: the dots are along the line
Weak: all over the place
Uncertainly: random variability (or error)
Less error in strong relationship
More error in weak relationship
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find more resources at oneclass.com
Document Summary
Variable: something can vary (e. g. gpa, gender, self-esteem ) Levels or values (what the variable varies on can be either quantitative; number or categories) E. g. temperature in a room, length of words that you read a book: response variable. E. g. how people sweat in a crowded room, reaction time, performance on a cognitive task: participant variable. Characteristics of individuals that they bring with them to a study e. g. gender, age, personality, traits, etc: mediating variable. A variable that occurs between situational variable and a response variable. E. g. helping is less likely when there are bystanders to an emergency. Operational definition: a definition of the variable in terms of the operational or techniques the researcher uses to measure or manipulate it. Defining helps us communicate our ideas to others. Non-experiment and experimental methods overview: non experimental method. Relationships are studied by observing or otherwise measuring the variables of interest.
