# PSY100H1 Chapter Notes - Chapter 5: Statistical Significance, Abnormal Psychology, Random Assignment

CHAPTER 5 – Research Methods in the study of abnormal behaviour

A Theory is a set of propositions meant to explain a class of phenomena. Primary goal of science is to

advance theories to account for data, often by proposing cause-effect relationships

In formulating a theory, scientist must often make use of theoretical concepts: unobservable states that

are inferred from observable data

J. Brett Barkley, clinicians prepare a Case Study by collecting historical and biographical information about

a single individual, often including experiences during therapy sessions

A Comprehensive case study would include family history, background, medical history,

educational background, jobs held, marital history, details concerning development, personality, life

course, and current situation

A case study may not reveal principles characteristic of people in general and is unable to provide

satisfactory evidence concerning cause-effect relationships

(chapter3) Epidemiology research focuses on determining three features of a disorder:

1. Prevalence: proportion of a population that has the disorder at a given point/period of time

2. Incidence: the number of new cases of the disorder that occur in the same period/year

3. Risk Factors: Conditions that increase the likelihood of developing the disorder

Correlational Method: establishes whether there is a relationship between/among 2 or more variables.

The variables being studied are measured as they exist in nature

Correlation coefficient (r): strength of the relationship between the two sets of variables (-1.00 to +1.00)

The higher the value of r, the stronger the relationship between the two variables therefore -1 and +1 are

the strongest while 0.00 indicates that they are unrelated

Statistical Significance: refers to the likelihood that the results of an investigation are due to chance (5/100

or less is considered as statistical significance.)

Statistical Significance Correlation: one that is not likely to have occurred by chance

Eg. A correlation of r=0.3 is statistically significant when the number of observations is large but wouldn’t

be if number of observations were 20.

The Directionality Problem is the correlation does not imply causation

Studies of two variables must show positive correlation or the theory will be disconfirmed

High Risk Method: only individuals with greater than average risk of developing disease in adulthood

would be selected for study

## Document Summary

Chapter 5 research methods in the study of abnormal behaviour. A theory is a set of propositions meant to explain a class of phenomena. Primary goal of science is to advance theories to account for data, often by proposing cause-effect relationships. A comprehensive case study would include family history, background, medical history, educational background, jobs held, marital history, details concerning development, personality, life course, and current situation. Correlational method: establishes whether there is a relationship between/among 2 or more variables. The variables being studied are measured as they exist in nature. Correlation coefficient (r): strength of the relationship between the two sets of variables (-1. 00 to +1. 00) The higher the value of r, the stronger the relationship between the two variables therefore -1 and +1 are the strongest while 0. 00 indicates that they are unrelated. Statistical significance: refers to the likelihood that the results of an investigation are due to chance (5/100 or less is considered as statistical significance. )