In the construction of cost of living index, commodities are selected by:

Explanation

In the constructing of cost of living index, the commodities are selected by judgement/purposive sampling. In this method of sampling the choice of the sample items depends exclusively on the judgement of the investigator

Simple random sampling = It is a sampling technique where every item in the population has an even chance and likelihood of being selected in the samplr

In it selection of items completely depends on chance or by probability  and each item has equal chance to be selected

It is also known as the method of chances

Stratified random sampling = With this sampling, the researcher divides the population into separate groups called strata. Then, a probability sample (often a simple random sample) is drawn from each group.

For example, Dividing the entire state into 3 - 4 geographical regions and then selecting a required sample of districts from each of these regions.

Systematic sampling = In this sample members from a large population are selected according to a random starting point but with a fixed, periodic interval and this interval is called sampling interval(k)