cohens d and D relationships/ 3 main types of studies

measures the DIFFERENCE between groups

ex: how much procrastination scores DIFFER between psych and chem majors, uses BAR graphs

cohens d guidelines

usually CORRELATIONS, CANT say that a change in x CAUSES a change in y, can be D OR R relationships, NO manipulation

we CAN say that a change in x CAUSES a change in y, often uses D relationships

MIX OF BOTH non-experimental and experimental research, does NOT MEET CRITERIA of an EXPERIEMENT, LACKS random assignment,

3 things experiments MUST have

we do NOT MANIPULATE them, may use placebos

AKA GROUPS, levels of the IV in an experiment, EX: quiet vs loud environments

participants have EQUAL chance of being in experiments or control groups, SUPPORTS causal conclusions, correlations are NEVER experiments

experiments address both...

directionality problem is solved because...

third variable problem is solved because of...