Correlations

• Define a correlational study

  -way of establishing whether there is a relationship between two variables

  -assessing the strength of that relationship
• How can you analyse a correlational relationship

  -Drawing a scatterplot​

  -Calculating a correlation coefficient
• What is a positive correlation

  -As one variable rises, so does the other
• What is a negative correlation

  -As one variable rises, the other falls
• The correlation coefficient indicates

  -the extent to which the pairs of numbers for these two variables lie on a straight line. Values over zero indicate a positive correlation, while values under zero indicate a negative correlation.
• The perfect correlation is 1.0

  +1.0 = perfect positive correlation​

  -1.0 = perfect negative correlation
• What are some strengths of correlations

  -Can be used when it is unethical or impractical to manipulate​

  variables and can make use of existing data. ​

  ​-It can tell us is further research is justified.

  -As with experiments procedures can be repeated again which​

  means the findings can be confirmed.
• What are some weakness

  -cannot establish cause and effect only relationships

  -may be third variable

  -may lack internal or external validity