Correlation

Correlation

1. Example core studies with correlational data

   • Physiological Approach
     • Dement & Kleitman
       • Laboratory Experiment
       • Measured the correlation between how long the sleeper had been in REM sleep and the length of their dream
     • Maguire
       • Quasi Experiment
       • Measured the correlation between length of taxi driver's experience and the structural change of the hippocampus

2. To calculate the correlation coefficient

   • To quantify the strength of relationship between two variables
   • Correlation Coefficient: A mathematical measure of the degree of relatedness between two sets of data where two scores have been gained from each participant
     • A value between -1 and +1
       • +1 = Perfect positive correlation
       • -1 = Perfect negative correlation

3. Data can be plotted on a scattergraph

   • With a line of best fit
   • Positive Correlation: Both variable increase
   • No Correlation: No line of best fit
   • Negative Correlation: One variable increases, the other decreases

4. Advantages

   • Allow researchers to calculate the strength of a relationship between variables quantitively
   • Correlation can make predictions about one variable from the other
   • More detailed research

5. Disadvantages

   • Can't assume one variable causes another
   • Correlation bewtween variables can be misleading/misinterpreted
   • No correlation may not mean there isn't a relationship because the relationship may be non-linear

6. Ethics

   • Researching relationships between socially sensitive subjects such as IQ and ethnicity can be misinterpreted as 'cause and effect'