causal relationships

• causation – when one variable causes a change in another
• correlation shows that there may be a link between two variables. correlation does not imply causation.
• example:

  causal relationship – increase in temperature = increase in ice cream sales

  correlation only – sales of chocolate and sales of clothes having a positive correlation.
• multiple factors – In real life situations there are usually multiple factors interacting to cause variables to change.
• example: a positive correlation between fat in liver and reaction time does not mean one causes the other. there could be a third variable, such as amount of alcohol consumed, which both variables depend on.