Correlation

Is correlational research an experimental or non-experimental method?

Non-experimental

Correlational research describes:

The relationship between two or more variables

What is the first step toward predicting behavior?

Describing it

Naturalistic observations and surveys often show us that:

One trait or behavior tends to coincide with another

When one trait or behavior coincides with another, we say that the two:

Correlate

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other

Correlation

What can reveal how strongly two variables are related?

Scatterplots

Each dot in a scatterplot represents:

The values of two variables

Types of correlations on scatterplots:

Perfect positive, no relationship, perfect negative

Graph of perfect positive correlation:

Graph of no relationship:

Graph of perfect negative correlation:

r value of perfect positive correlation:

+1.00

r value of no relationship:

0.00

r value of perfect negative correlation:

-1.00

r values can range from:

+1.00 to -1.00

r value is +1.00 when:

Scores for one variable increase in direct proportion to scores for another variable

r value is -1.00 when:

Scores for one variable decrease precisely as scores for the other variable rise

Are perfect correlations rare in the real world?

Yes

Does a negative correlation mean that it is not strong?

No

Is a negative correlation bad?

No

Example of a perfect negative correlation:

People’s height vs distance from their head to the ceiling

Statistics can reveal:

What we might miss with casual observation

Example of how statistics reveal what we might miss with casual observation:

We can easily see evidence of gender discrimination when given statistically summarized information about job level, seniority, performance, gender, and salary, but not when the information dribbles in case by case

What do single events or individuals do to us?

Catch our attention

When especially do single events or individuals catch our attention?

When we want to see (or deny) bias

How do statistics calculate patterns?

By counting every case equally

Two problems with correlational research:

Directionality and third variable problem

What does directionality problem mean?

Correlational research cannot tell us which variable is the cause and which one is the effect

Example of directionality and third variable problem:

If mental illness correlates with smoking, it could be smoking that leads to mental illness or mental illness to leads to smoking, or a third variable, like a stressful home life, that causes both smoking and mental illness

Benefits of correlations:

Make clear relationships we might miss, and keep us from falsely assuming a relationship exists when there is none

A statistical index of the relationship between two variables:

Correlation coefficient

Anything that can vary and is feasible and ethical to measure:

Variable

A graphed luster of dots, each of which represents the values of two variables:

Scatterplot

The slope of the points on a scatterplot suggests the:

Direction of the relationship between the two variables

The amount of scatter on a scatterplot suggests:

The strength of the correlation

Little scatter indicates high or low correlation?

High

Illusory correlations happen when:

We believe that there is a relationship between two things

What happens when we believe that there is a relationship between two things?

We may notice and recall confirming instances more than disconfiming instances

Perceiving a relationship where none exists, or perceiving a stronger-than-actual relationship

Illusory correlation

Example of illusory correlation:

If we believe that dreams forecast actual events, we may notice and recall confirming stances more than disconfirming instances

Illusory correlations cause us to feel that:

We can personally influence chance events

Example of how illusory correlations cause us to feel that we can personally influence chance events:

If gamblers remember only past lucky rolls, they may believe that they influenced the roll of the dice by throwing gently for low numbers and hard for high numbers

The illusion that uncontrollable events correlate with our actions is caused by:

Illusory correlations and regression towards the mean

The tendency for extreme or unusual scores or events to fall back towards the average

Regression toward the mean

What causes extreme results?

Unfortunate combinations

Example of regression towards the mean:

Lower than expected test score could be caused by an unfortunate combination of test topic, question difficulty, sleep, and weather, and this combination may not happen again so the next score will regress back to the average

Extraordinary happenings tend to be followed by:

More ordinary ones

Failure to recognize regression towards the mean can cause:

Superstitious thinking

Example of superstitious thinking caused by failure to recognize regression towards the mean:

If a coach berates a team for a poorer-than-normal performance and the next time performance regresses back to normal, the coach would think that the scolding worked

Regression toward the mean can mislead us into feeling what after criticizing others?

Rewarded

Regression toward the mean can mislead us into feeling what after praising others?

Punished

Can you use fancy explanations to explain why a fluctuating behavior returns to normal?

Usually not