The total of 60 households is a sample (4) and a stratified sample (2). It is a sample because it is selected from the total population and is therefore a subset of that population. It is a stratified sample because separate samples are selected from different categories of individuals who are identified on the basis of a common attribute. In this particular case, individuals are selected randomly as long as they fall within a specifically defined income category.

The 60 households selected are therefore clearly not a population. Nor do they constitute a sample with random assignment, which is a process in which an overall random sample from a population is then assigned to categories based on criteria not related to them personally. An example of this would be a medical test involving a group of randomly selected individuals who are then assigned to one of three categories, each of which will then receive a different drug. It is also clearly not a simple random sample because once an income category is full during the selection process, individuals meeting the criterion of that category will be rejected. Further, there is no evidence provided to suggest that the population contains equal numbers of individuals in each of the income categories.