PSYC 217 MIDTERM REVIEW SESSION

October 15, 2008

NONEXPERIMENTAL METHOD

 Relationships are studied by making observations or measure of the variables of interest  Correlational method   Relationship is established by looking at how two variables vary together 2 problems with making causing statements   1. hard to determine direction of cause and effect 2. third-variable problem

EXPERIMENTAL METHOD

 One variable is manipulated and the other is measured  Able to say something about the direction of cause and effect  IV = cause  DV = effect

CONSTRUCT VALIDITY

 Refers to the adequacy of the operational definition of variables  Refers to whether the measure for a certain construct adequately represents what is intended by theoretical account of the construct being measured

INTERNAL & EXTERNAL VALIDITY

 Internal validity: Refers to the ability to draw conclusions about causal relationships from our data  Estimates of the degree to which conclusions about causes of relations are likely to be true  External validity: Extent to which the results can be generalized to other populations and settings

RELIABILITY

 Refers to the consistency of a measure  True score  Actual score on a variable being measured, as opposed to the score obtained on the measure itself  Measurement error  Degree to which a measurement deviates from the true score

CRITERION-ORIENTED VALIDITY

 Predictive validity: Scores on a measure that predicts some future behaviour  Concurrent validity: Scores on one measure are related with another measure of the same construct carried out at the same time  Convergent validity: Scores on one measure are related to scores on other measures of the same construct  Discriminant validity: Scores on a measure at not related to other measures that are supposed to be different

MEASUREMENT SCALES

 Nominal: Categories with no numerical scales  Ordinal: Rank ordering with limited numerical values  Interval: Numeric properties are literal with equal interval between values  Ratio: Zero indicates absence of variable measured

REMINDER!

 1) You will need a PICTURE ID to turn in your exam! Exams will not be accepted and you will receive a zero if you do not have a picture ID with you.  2) You must take the exam in the section you are registered for. The two sections have different exams. If you take the wrong exam, you will receive a zero!

 3) No hats, baggy clothes, scarves or electronic devices will be allowed on exam day. Make sure you keep cell phones, pagers, etc. stowed.