Research Methods chapter 8 Bivariate Correlational Research

Bivariate correlations

associations that involve exactly two variables

what makes a study correlational?

having two measured variables

construct validity

how well was each variable measured

statistical validity

how well do the data support the conclusion?

internal validity

can we make a casual inference from an association?

external validity

to whom can the association be generalized?

effect size

describes the strength of an association between two or more variables

What are some questions to determine construct validity?

“How well was each of the variables measured?”

“Does the measure have good reliability?”

“Is it measuring what it’s intended to measure?”

“What is the evidence for its face validity, for its concurrent validity, and for its discriminant and convergent validity?”

What are some questions to determine statistical validity

“How strong is the relationship?”

“How percise is the estimate?”

“Has it been replicated?”

“Could outliers be affecting ther association?”

“Is there restriction of range?”

“Is the association curvilinear”

association claim

describes the relationship found between two measured variables

statistically significant

p < .05, it's unlikely that the reuslt came from the null hypothesis population

outliers

extreme scores, higher or lower than other scores

restriction of range

bivariate correlation, the absence of the full range of possible scores, the relationship from the sample underestimates the correlation

Directionality problem

in a correlational study, the occurence of both variables being measured around the same time, making it unclear which variable in the association came first

third-variable problem

the existence of a possible alternative explaination for the outcome

suprious association

bivarriate correlation exists, but only because of 3rd variable

moderator

variable, depending on its level, changes the relationship between two other variables