Heterogeneous denotes to a form with different components or features, give the impression as uneven or varied.
A heterogeneous population or sample is the one where each and every individual has a diverse value for the distinctive characteristic one is interested in.
To select a representative sample from the random heterogeneous material one should divide the material into segments and then use random number, either by the random number table or by the random number generator, to select random segments of the material.
