Correlations

• Correlation

  • Looks at relationship of two variables known as co-variables
• Types of correlations

  • Positive correlation
  • Negative correlation
  • None
• Positive correlation

  • As one variable increases the other co-variable also increases
• Negative correlation

  • As one variable increases the other co-variable decreases
• Zero correlation

  • No association
• Correlation co-efficient

  • Strength of relationship
  • +1 is positive and -1 is negative perfectly
• Advantages of correlations

  • Measure relationships
  • Indicate trends
  • Shows both direction and strength of relationship so can make predictions
• Disadvantages of correlations

  • Not possible to draw conclusions about cause and effect lowering the validity
  • Extraneous variables may influence results
  • Sample