There is no argument that the significance attached to the vital role played by sampling theory in statistics cannot be
overemphasized considering its vast number of applications in different spheres of life. The application of sampling theory is not
only limited to the sample selection, but also to the information about the population of its parameters. The main objective of
sampling theory is to estimate the parameter of interest using some statistical properties as a bedrock. In many situations, it happens
that information regarding some variables apart from the variables of interest (study variables) can easily be collected. This
information is called auxiliary information which is formed by auxiliary variable(s).
