correlations

• correlation = mathematical technique that is used to investigate an association between 2 variables - co-variables.

  different to experiments as variables only measured not manipulated, only association found not cause and effect relationship.
• correlation coefficients calculated, determines strength and relationship between 2 variables.
• • negative correlation: one increases, other decreases. line of best fit negative gradient. correlation coefficient = less than 0
  • positive correlation: one increases, the other increases. positive gradient. correlation coefficient = more than 0
  • zero correlation: no relationship, no line of best fit. correlation coefficient = 0
• .

  A) negative

  B) zero

  C) positive

  
• correlations

  + can be used as starting points to assess patterns before experimental study

  + quick and economical

  - could be third variable

  - tend to be misused and misinterpreted