Flashcards in Chapter 8 Deck (20):
associations that involve exactly two variables
also called bivariate associations
Statistic to test the difference between two group averages
It is still possible to calculate an r value, but a t test is more commonly used.
What makes a study correlational?
Having two measured variables, using either a bar graph of scatter plot
How well was each variable measured
How do the data support the conclusion
Can we make a casual inference frmo association?
To whom can the association be generalized?
describes the strength of an association.
How close they stick to a line
didn’t find the result by chance.
refers to the conclusion researchers make regarding how probable it is that they would get a correlation of that size by chance, assuming that there is not a correlation in the real world
Provides information about statistical significance by evaluation the probability that the association in the sample came form a population with an association of zero
dependent on sample size and effect size.
An extreme score
Restriction of range
When there is not a full range of scores on one of the variables in an association in a correlational study, it can make the correlation appear smaller than it really is.
Correlation Coefficient is zero (or close to zero), and the relationship isn’t a straight line.
The Three Criteria for Establishing Causation
Covariance, Temportal precedence ( the directionality problem), Internal validity (third-variable problem)
There must be an association between the cause variable (A) and the effect variable (B).
Temporal precedence (the directionality problem):
The causal variable (A) must come before the effect variable (B).
Internal validity (third-variable problem)
Is there a third variable (C) that is associated with variables A and B independently? If so, then we can’t infer causation.
one that is only present because of a third variable