Correlations Flashcards
Define ‘correlation’
A measurement of the extent to which two co-variables are related
Define ‘positive correlation’
When both variables increase together
Define ‘negative correlation’
When one variable increases as the other decreases
What indicates the strength of a correlation?
A correlation coefficient
What coefficient constitutes as a positive correlation?
One above zero
What value is a perfect positive correlation?
+1
What coefficient constitutes as a negative correlation?
Below 0
What value is a perfect negative correlation?
-1
What methods obtain correlational data?
- Questionnaires
- Observations
- Experiments
Define a ‘curvilinear relationship’
Both variables increase together until a certain point, then as one variable continues to increase, the other decreases
In 7 steps, describe how you would analyse a correlation using a Spearman’s Rho
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
Evaluate 2 strengths of correlations
1- 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
2- 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
Evaluate 2 weaknesses of correlations
1- Low reliability due to using secondary data which may be out-of-date or have inconsistencies with current data meaning comparisons cannot be easily made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
