How can we establish and quantify a cause and effect relationship between two variables?
• Identify the response and explanatory variables from a plot. • response: y-variable, dependent • explanatory: x-variable, independent • Identify positive and negative associations from scatter plots. Note: an association does not establish cause and effect • Detect linear and non-linear relationships using scatter plots. Note: ALWAYS make a scatter plot when analyzing bivariate data • Judge the relative strength of a relationship by the amount of scatter around the curve of best fit. • Identify outliers on scatter plots. • Within the expected range X-values • Outside the expected range of Y-values for a given X-value • Identify “influential outliers” on scatter plots. • Outside the expected range X-values • Note: in this region the expected range of Y-values is undefined • Make scatter plots using the TI-83 calculator and Excel. • State why any analysis of 2 variable (bivariate) data should always begin with a scatter plot regardless of which tools are used to further analyze the dat
