2. Two Basic Approaches to Doing Research in Psychology Correlational Research Experimental Research Both approaches are based on the concept of a “variable”. Basically, a variable is anything that can vary, like your height, weight, age, address, and course schedule. It has two aspects: an overall dimension or continuum, and a series of “levels” or subdivisions.

3. Nature of a Variable It’s like a ruler... Not this kind of ruler: This kind: The ruler as a whole is the variable. We can name it “length”. The inch marks are the levels of the variable.

4. Nature of a Correlation A correlation is a relationship between two variables where changes in one variable go along with changes in the other variable. Like height and weight: As heights increase, weights also tend to increase.

5. Two Basic Kinds of Correlations: Positive: the variables change in the same direction, like height and weight. Negative : the variables change in opposite directions, like: as class absences increase, grades tend to decrease. Positive and Negative

6. The Coefficient of Correlation A value of 0.00 means there is no relationship between the variables. A value of +1.00 means a perfect, positive correlation. Weaker positive correlations have values higher than.00 but lower than +1.00. A value of -1.00 means a perfect, negative correlation. Weaker negative correlations have values higher than –1.00 but lower than 0.00. a measure of the strength of a correlation