Hypothesis testing approach
- Research begins with a theory, ( a general statement about the possible relationship between variables.) Hypothesis is a formal prediction derived from the theory, and it is
- formulated in a way that can lend itself to be tested.
Characteristics of a good theory. (p20)
Good theory- is parsimonious- uses as few variables as possible, and useful-lends itself to research.
A procedure that tells us how two variables vary together- that is- change in one variable is associated with change in another variable. Does no identify cause-and-effect relationships. Described along its magnitude, from -1 to 1, and direction=positive, negative, or no correlation.
vs. non-manipulated independent variables.- study very well!
- A procedure that enables us to identify cause-and effect relationships. We manipulate the Independent Variable (IV) to assess its influence on the Dependent Variable (DV). To Manipulate the IV means to create different levels of it.For example: If we want to assess the impact of sleep deprivation on concentration, we will create different levels of sleep- to see whether those who sleep more are able to concentrate better than those who sleep less (note issue of
- random assignment). The Independent Variable: the one that is theorized to affect, influence, another variable (the dependent variable). Random assignment of participants into the various experimental groups (e.g. sleeping 8 hours, 5 hours, 3 hours etc) eliminates any pre-existing differences among the participants. NON MANIPULATED INDEPENDENT VARIABLES-
- In many situations we are not able to randomly assign participants into groups. The groups already exist. For example: The impact of divorce of children’s academic performance. In such cases we cannot determine cause-and-effect relationships. The results are presented as correlations
Statistical significance and correlation
- A procedure that tells us the extent
- to which a result in experiment reflects real differences among the groups, or chance fluctuations. Is expressed in terms of probability – EX> result that is found to be significant at 5% tells us that there is a 95% probability that the result reflects true differences among the subjects, and not random factors.
The case-study method and its limitations
Oldest form of study. Involves studying one person in depth, often along time. Useful when there is a rare case that otherwise is difficult to study. Also useful to show the results of therapy. May also be subject to bias. Difficult to generalize to others.
Personality assessment: concepts of reliability, test-retest, and internal consistency.
- Personality tests need to possess psychometric qualities. Reliability- extent to which the results of test show consistency along time. – one form of assessing reliability is “test-retest” administering the test to the same person at two different points in time.- Reliability can also be assessed as “internal consistency”- the extent to which the items of the test correlate with the
- overall score.
validity- congruent and discriminant validity
- The extent to which the test measures
- what is claims to measure. Different forms of validity. Criterion-related. Concurrent. Construct validity,