Chapter 12 Flashcards
What is the correlational research strategy?
when two or more variables are measures to obtain a set of scores (usually two scores) for EACH individual. The measurements are then examined to identify any patterns of relationship that exist between the variables and to measure the strength of the relationship.
What is the purpose of the correlational research strategy?
establish and DESCRIBE a relationship between variables.
What kind of study is very similar to correlational research? Explain what it is.
Differential reproach (non-experimental design). It establishes the existence of a relationship by demonstrating a difference between groups.
What is a positive relationship?
tendency for two variables to change in the same direction; as one variable increases, the other also tends to increase.
What is a negative relationship?
tendency for two variables to change in opposite directions; increases in one variable tend to be accompanied by decreases in the other.
What is a monotonic relationship?
It’s when a relationship is consistently one-directional, either consistently positive or negative. The amount of increase need NOT be constantly the same size. Ex: practice and performance.
What is a Spearman correlation?
used to measure and describe monotonic relationships when both variables are ranks from an ordinal score or have been transferred to ranks
What is a correlation or a correlational coefficient?
Numerical value that measures and describes the relationship between two variables.
What is the coefficient of determination?
the squared value of a correlation and measures the percentage of variability in one variable that is determined, or predicted, by its relationship with another variable.
What is The Pearson correlation (r) coefficient?
It’s the statistic that indicates the degree to which two variables are related to one another in a linear fashion.
Go over the table for the minimum r that is significant for participants
In docs
When multiple correlations are used, the results are typically shown in a _______ _______
Correlation Matrix
A correlation does NOT imply ______
Causality!!!
What Three criteria must be satisfied to conclude that one variable causes another?
- Covariation.
- Directionality.
- Elimination of extraneous variables.
What is covariation?
There is a correlation (association) between variables X and Y.
What is directionality?
Variable X (the cause) precedes Variable Y (the effect).
What is the elimination of extraneous variables?
No other variable may be responsible for the relationship between X and Y.
What is illusory correlation? Give an example
A mistaken perception that two events are related when they are not. It is caused by a tendency to forget unremarkable counter-evidence.
Ex: Does a relationship exist between the moon phases and mental illness?
What is the directionality problem?
Correlational studies DO NOT allow us to determine which variable is the cause and which variable is the effect.
Ex: Self-Esteem and School Achievement
What is the third-variable problem?
Although a correlational study may establish that two variables are related, it does not necessarily mean that there is a direct relationship between them.
What are linear regressions used for?
Another way of looking at the relation between two variables.
The best fitting linear function is estimated and then used to “explain” the changes in one variable using a second variable.
What is the criterion?
The variable to be explained. (y) → “dependent variable”
What is the predictor?
Predictor. The variable used to predict, to “explain”. (x) “independent variable”
What does it mean to “explain variance”?
as one variable changes, we can predict changes to a certain extent in the other. The stronger the association between two variables, the better the prediction about the change in the other.
r^2 is the _________?
measure of effect size for regressions.
What is Multiple Regression?
Regressions allow for multiple predictors.
Example. Suppose you want to explain grades using both IQ and number of hours of study. (an additional predictor)
