Correlation

Question 1

What is the correlation in simple terms?

Answer 1

Correlation refers to a relationship (might be causal but might not) between two variables

Question 2

What is the correlation in scientific terms?

Answer 2

Correlated variables are non-independent (i.e. if you vary one you tend to get a predictable change in the other)

Question 3

A relationship (might be causal but might not) between two variables is known as…?

Answer 3

Correlation

Question 4

How do we measure the amount of correlation?

Answer 4

Covariance

Question 5

The extent to which a change in one variable is associated with predictable changes in a another variable – i.e. the extent to which they vary together

This is known as…?

Answer 5

Covariance

Question 6

Define covariance

Answer 6

The extent to which a change in one variable is associated with predictable changes in another variable – i.e. the extent to which they vary together

Simply = as variable y increases, to what extent will variable x also increase or decrease

Question 7

Are 2 variables related?

Is this a research question investigating causal or correlational relationships?

Answer 7

Correlational relationships

Question 8

There will be a relationship between pie eating and weight such that the more pies eaten the heavier people will be

Is this a hypothesis investigating causal or correlational relationships?

Answer 8

Correlational relationships

Question 9

True or False?

Causality can be inferred from correlation

Answer 9

False

Causality cannot be inferred from correlation

Question 10

True or False?

Just because 2 variables are correlated, does not mean we should conclude that they have causal relationships

Answer 10

True

Question 11

If we can’t assume that one variable causes another, why do they still have a correlational relationship?

Answer 11

Because there is an underlying variable that causes both of the variables to be related to each other

Question 12

What are the 4 types of correlation?

Answer 12

1) Perfect positive
2) Perfect negative
3) Imperfect positive
4) Imperfect negative

Question 13

Define perfect positive correlation

Answer 13

As variable x increases, variable y also increases at the same rate

Straight line going up

Question 14

Define perfect negative correlation

Answer 14

As variable x increases, variable y decreases at the same rate

Straight line going down

Question 15

Define imperfect positive correlation

Answer 15

As variable x increases, variable y also increases but not at the same rate

Not a straight line going up

Question 16

Define imperfect negative correlation

Answer 16

As variable x increases, variable y decreases not at the same rate

Not a straight line going down

Question 17

What type of correlation is this?

As variable x increases, variable y also increases at the same rate

Straight line going up

Answer 17

Perfect positive

Question 18

What type of correlation is this?

As variable x increases, variable y decreases at the same rate

Straight line going down

Answer 18

Perfect negative

Question 19

What type of correlation is this?

As variable x increases, variable y also increases but not at the same rate

Not a straight line going up

Answer 19

Imperfect positive

Question 20

What type of correlation is this?

As variable x increases, variable y decreases not at the same rate

Not a straight line going down

Answer 20

Imperfect negative

Question 21

What are the 3 ways to measure linear correlation between 2 variables?

Answer 21

1) Pearson’s r statistic
2) Spearman’s rho
3) Relationships between categorical variables with frequency data using Chi-square

Question 22

Correlation coefficient is measured by….?

Answer 22

Pearson’s r statistic

Question 23

What does Pearson’s r statistic allow us to do?

Answer 23

Allows us to conduct a formal analysis to test hypotheses regarding the presence of a linear relationship between variables

Question 24

When two variables are negatively correlated an increase in one variable will tend to be accompanied by a decrease in the other variable.

a. True
b. False

Answer 24

a. True

Question 25

In a correlational research design, we commonly manipulate an independent variable and then look for the effect of this manipulation on a dependent variable.

a. True
b. False

Answer 25

b. False

Question 26

When two variables have a strong positive correlation the implication is that increasing one variable typically causes the other variable to increase

a. True
b. False

Answer 26

b. False