2.1 Exploratory Data Analysis

Classical methods of statistical inference depend heavily at least on the following assumptions:

• The data are outlier-free.
• The data are nearly normal.

In addition, certain statistical techniques (e.g., multiple regression) require that:

• The relationships of independent variable(s) with dependent variable are linear.
• Independent variables themselves are not highly correlated.

The following graphical techniques available in IDAMS module – GRAPHID – can provide useful insights into the nature of the data.

• Histogram
• Box and whisker plot
• Scatter plot