Research Methods- Correlations

Question 1

The difference between correlations and experiments:

Answer 1

Experimental designs require manipulation of the independent variable and a measurement of the resulting change in the dependant variable. In a correlational study, no variables are manipulated, two co-variables are measured and compared to look for a relationship.

Question 2

Co-variables

Answer 2

the two factors/ variables that are measured/ collected by the researcher and then compared to each other.

Question 3

Example co-variables

Answer 3

Age
IQ
Reaction time
Bank account balance
Number of pets
Hight
Hostility level

Question 4

Scattergram:

Answer 4

A graph used to plot the measurements of two co-variables.
Scattergrams visually display the relationship between co-variables.

Question 5

Positive correlation:

Answer 5

As one co-variable increases the other co-variable increases

Question 6

Negative correlation:

Answer 6

As one co-variable increases the other co-variable decreases

Question 7

Zero correlation:

Answer 7

There is no relationship between the values of the two co-variables

Question 8

Analysis of the relationship between co-variables:

Answer 8

The strength and direction of a correlation can be described visually with a scattergram, or numerically with a correlation coefficient.

Question 9

Correlation coefficient:

Answer 9

Represents both the strength and direction of the relationship between the co-variables as a number between -1 and +1

-1
Perfect negative

-0.8, -0.5, -0.2
Strong. Moderate. Weak negative

0
No correlation

0.2, 0.5, 0.8
Weak. Moderate. Strong positive

+1
Perfect positive

Question 10

How are Correlation coefficients calculated?

Answer 10

Correlation coefficients are calculated using statistical tests such as Spearman’s rho or Pearson’s. Inter-rater and test-retest reliability is assessed in this way. A correlation coefficient equal to or greater than 0.8 is usually judged to show a strong correlation.

Question 11

Correlation evaluation
❌

Answer 11

•Correlation does not show causation. While a strong correlation may suggest a relationship exists between two variables, it does not show which co-variable led to the change in the other co-variable and there is the possibility that an unknown third variable caused the change in both covariables.

Question 12

Correlation evaluation
✅

Answer 12

• Correlational studies can highlight potential causal relationships, these can then be tested with experimental methods to discover cause and effect relationships.

• Often the covariable data already exists and is easily accessible, this means there is usually few ethical problems in data collection.

• Correlation coefficient is a useful tool in describing both the direction and strength of relationships between factors.