Chapter 2 Research Process Part 2: Sept. 1, 2010

Research Process steps (cont.) Random sampling and random assignment – Results of random sampling example: – Results of random assignment example: More on construct validity (and survey wording)

The Correlational Method: determines if two variables are related – Correlation coefficient: Positive, negative, or no correlation? Most studies using this method are field studies. Cannot make cause-effect conclusions. – Often a third variable can explain relations between 2 variables under study – Example? Need experiments to determine cause-effect

Experimental Methods: manipulate variables in attempt to examine cause  effect About 3/4ths of Social Psych research. Most is done in lab settings. 2 distinguishing factors: – 1. – 2.

Experiment Examples – From book, Greitemeyer (2009) “song lyrics and helping” Manipulation? Results? – (not in book), Schneider et al (2001) “harassment and heart rate” Manipulation? Results?

Advantages of Correlational vs. Experimental Research Adv of Corr Research: – 1) – 2) Adv of Exp Research: – 1) – 2)

Step 4: Interpreting results Independent variables: what is manipulated – Examples? Song lyrics study – Harassment study – Dependent variables: observed to determine impact of IV – Examples? Song lyrics study – Harassment study -

Subject variables: cannot be manipulated – Examples - Statistical significance: – Need to determine how likely it is we’d get these results just by chance. – What is the standard convention used?

External validity – questions related to whether results will generalize – How can this be assessed? Problems with convenience samples – Mundane realism – Experimental realism - Internal validity – questions related to whether IV causes effects on the DV – How can this be assessed? Use of control groups – Experimenter expectancies -