# Linear and nonlinear relationships between variables

Linear and Nonlinear Relationships Between Variables
How two things are related or the degree to which they are related is often a question in any area of research, including forensic psychology research. A researcher might ask these questions: To what degree are drug use and criminal recidivism related? Are mental illness and violence related? To what degree is an increase in police patrols related to a decrease in crime rates?
Each of these forensic psychology research questions can be addressed using a correlational design. Correlational designs help determine if there is a relationship between variables. The relationship may be positive, meaning there is a positive linear relationship between the two variables; the relationship may be negative, which means there is a weak or nonexistent linear relationship between the two variables; or, the relationship may be curvilinear, which means that at times there appears to be a relationship and at times there does not.
To prepare for this Discussion:

Review Chapter 9 in your course text, Research Methods for the Behavioral Sciences. Pay attention to the descriptions and examples of linear and nonlinear relationships, positive and negative linear relationships, and curvilinear relationships.
Consider how these relationships are determined and what impact each type of relationship may have on a researcher’s ability to make predictions.
Using the Walden Library, select and review two or three articles on criminal recidivism, violent crime, or domestic violence in which the variables have positive and negative linear relationships.

With these thoughts in mind:
Post by Day 4 a description of two variables that have a positive linear relationship and two variables that have a negative linear relationship in the research articles you reviewed. Then, explain the implications on the studies if each of those variables had a curvilinear relationship instead.
Be sure to support your postings and responses with specific references to the Learning Resources.

Linear and nonlinear relationships between variables

Linear and Nonlinear Relationships Between Variables
How two things are related or the degree to which they are related is often a question in any area of research, including forensic psychology research. A researcher might ask these questions: To what degree are drug use and criminal recidivism related? Are mental illness and violence related? To what degree is an increase in police patrols related to a decrease in crime rates?
Each of these forensic psychology research questions can be addressed using a correlational design. Correlational designs help determine if there is a relationship between variables. The relationship may be positive, meaning there is a positive linear relationship between the two variables; the relationship may be negative, which means there is a weak or nonexistent linear relationship between the two variables; or, the relationship may be curvilinear, which means that at times there appears to be a relationship and at times there does not.
To prepare for this Discussion:

Review Chapter 9 in your course text, Research Methods for the Behavioral Sciences. Pay attention to the descriptions and examples of linear and nonlinear relationships, positive and negative linear relationships, and curvilinear relationships.
Consider how these relationships are determined and what impact each type of relationship may have on a researcher’s ability to make predictions.
Using the Walden Library, select and review two or three articles on criminal recidivism, violent crime, or domestic violence in which the variables have positive and negative linear relationships.