Exam 4 Cheat Sheet

Exam 4 Cheat Sheet - Quasi-experimental Methods:...

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(9)Correlations vary in their Magnitude: an indication of the strength of the relationship between 2 variables. Indication of the strength of the relationship between 2 (or more) variables. Positive relationships : go in the same direction, an increase or decrease in one is related to an increase or decrease in the other(from the lower left corner to the upper right corner). Negative relationship: (upper left to the lower right) an increase in one variable is accompanied by a decrease in the other. (more of variable x means less of variable y). No relationship: the points are scattered randomly. Curvilinear Relationships: as a correlation coefficient of 0 means no relationship, it can also mean that there is curvilinear relationship(u-shape) Determined by correlation coeffiecient . Ranges from -1 to +1 – perfect, 0 – none.Strong.7 to 1 (pos or neg).Moderate .3 to .69.None to weak 0 to . 29. Scatterplot: a figure the graphically represents the relationship between 2 variables. Causality: the assumption that a correlation indicates a causal relationship between 2 variables. Directionality: the inference made with respect to the direction of a causal relationship between 2 variables(assuming that one variable is the cause of another variable: illiteracy is the cause of drug use). Third-variable problem: the problem of a correlation between 2 variables being dependent on another (3 rd ) variable (hidden variable that). A way to test this 3 rd variable problem is by using the Partial correlation: a correlational technique that involves measuring 3 variables and then statistically removing the effect of the 3 rd variable from the correlation of the remaining 2. Restrictive range: a variable that is truncated and has limited variability (range of window). Person-who argument: arguing that a well-established statistical trend is
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This note was uploaded on 09/14/2011 for the course PSY 290 taught by Professor Cate during the Spring '11 term at ASU.

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