Sampling bias can be intentional or intentional. Sampling bias refers to the systematic distortion of a sample that can occur. It is caused by such factors as the methods used to select a sample. A biased sample will not produce data that can be applied validly to the entire population. Sample types include probability and non-probability.
Probability samples are simple random, systematic random, stratified random, and cluster.
Non-probability samples are convenience, purposive, snowball, and quota. Measurement Concepts Measurement is the process of sorting and quantifying information on the variables of the study. Measurement instruments such as questionnaires are used for measuring variables. Levels of measurement refer to the degree of precision with which that level supposedly measures variables. Nominal is the most basic and merely names the variables.