C2 Looking at Data - Relationships

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Terms in this set (...)

responsible variable
measures an outcome of a study
explanatory variable
explains or causes changes in the response variable
correlation
measures the direction and strength of the linear relationship between two quantitative variables;
residual
difference between an observed value of the response variable and the value predicted by the regression line

residual = observed - predicted y
= y - y hat
lurking variable
variable that is not among the explanatory or response variables in a study;
and yet may influence the interpretation of relationships among those variables
Simpson's paradox
refers to the reversal of a comparison by aggregation;
an association or comparison that holds for all of several groups can reverse direction when the data are combined to form a single group
When are two variables confounded?
when their effects on a response variable cannot be distinguished from each other;
the confounded variables may be either explanatory variables or lurking variables or both