When the available population is _____, we use a stratified sample.a) too smallb) very largec) homogeneousd) heterogeneous

We use a stratified sample when the available population is d) heterogeneous.

Here's why:

Stratified sampling is a method of sampling that involves dividing a population into smaller groups known as strata. The strata are formed based on shared characteristics or attributes such as income level, education level, gender, race, or age.

This method is used when the population is heterogeneous, or diverse, and you want to ensure that the sample represents this diversity. By dividing the population into strata, you can ensure that the sample includes a proportional representation of each stratum, making the sample more representative of the population as a whole.

In contrast, when the population is too small (a), very large (b), or homogeneous (c), other sampling methods may be more appropriate. For example, simple random sampling could be used when the population is homogeneous, as each individual in the population is similar and therefore has an equal chance of being selected.