Ch4: Correlation

• What is bivariate data?

  Data which has paid of values for two variables
• how do you represent bivariate data?

  scatter diagram
• What is correlation?


  Describes the nature of the linear relationship between two variables
• What does it mean when two variables have a casual relationship?

  a change in one variable causes a change in the other

  just because two variables have correlation, doesn’t mean they have a casual relationship
• What is the equation of a regression line?

  Y= a + bx
• what does the coefficient of b show in a regression line?

  the change in y for each unit change in x

  if the data is positively correlated, b will be positive

  if the data is negatively correlated, b will be negative