Methodology: Correlations

Question 1

Define ‘correlation’.

Answer 1

A measurement of the extent to which two co-variables are related.

Question 2

Define ‘positive correlation’.

Answer 2

When both variables increase together.

Question 3

Define ‘negative correlation’.

Answer 3

When one variable increases as the other decreases.

Question 4

What indicates the strength of a correlation?

Answer 4

A correlation coefficient.

Question 5

What coefficient constitutes as a positive correlation?

Answer 5

One above zero.

Question 6

What value is a perfect positive correlation?

Answer 6

+1

Question 7

What coefficient constitutes as a negative correlation?

Answer 7

One below zero.

Question 8

What value is a perfect negative correlation?

Answer 8

-1

Question 9

What methods obtain correlational data?

Answer 9

• Questionnaires
• Observations
• Experiments

Question 10

List 3 methods of analysing correlational data.

Answer 10

1) Ranking 2 sets of data
2) Using a scattergram
3) Spearman’s Rho

Question 11

Describe how you would analyse a correlation using ranks.

Answer 11

• Rank 2 sets of data and compare
• If high ranks match with high ranks then it’s positive
• If high ranks match with low ranks then it’s negative

Question 12

Describe how you would analyse a correlation using a scattergram.

Answer 12

Plotting the co-variables on a scattergram with a line of best fit to establish the correlation coefficient from the gradient.

Question 13

Define a ‘curvilinear relationship’.

Answer 13

Both variables increase together until a certain point, then as one variable continues to increase, the other decreases.

Question 14

In 7 steps, describe how you would analyse a correlation using a Spearman’s Rho.

Answer 14

1) Rank both data sets separately
2) Work out the difference between the ranks
3) Square the difference and total it
4) Multiply the total of squared differences by 6
5) Square the number of ppts and subtract 1 then multiply by number of ppts
6) Divide step 4 by step 5
7) Subtract the total from 1

Question 15

Evaluate 4 strengths of correlations.

Answer 15

1) High reliability due to the easily replicable methods used to gather the quantitative data for simple comparisons to repeat and test for consistency
2) High validity due to controlling for ppt variables as both covariables will be completed by the same person therefore individual differences will not affect the correlation
3) Highly ethical due to allowing us to investigate otherwise unethical situations if experimented on such as it being unethical to study the number of cigarettes smoked and lung capacity by getting someone to start smoking
4) Correlations can lead to new research as they highlight areas which have relationships therefore need to be researched more to find a cause and effect relationship

Question 16

Evaluate 3 weaknesses of correlations.

Answer 16

1) Low reliability due to using secondary data which may be out-of-date or have inconsistencies with current data meaning comparisons cannot be easily made
2) Low validity due to not being able to establish a causal relationship
3) Low validity due to often using self-report questionnaires that lead to social desirability