Biostatistics in research methodology

[Guest guest]

1. Dear Members,

Convenience

or opportunistic sampling is the crudest type of non-random sampling.

This involves selecting the most convenient group available (e.g. using the

first 20 colleagues you see at work). It is simple to perform, but is unlikely

to result in a sample that is either representative of the population or

replicable.

A commonly used non-random method of

sampling is quota sampling, in which a pre-defined number (or quota) of

people who meet certain criteria are surveyed. For example, an interviewer may

be given the task of interviewing 25 women with toddlers in a town centre on a

weekday morning, and the instructions

may specify that seven of these women should be aged under 30 years, ten should

be aged between 30 and 45 years, and eight should be aged over 45 years. While

this is a convenient sampling method, it may not produce results that

are representative of all women with children of toddler age. For instance, the

above example will systematically exclude women who are in full-time

employment. Regards,Dr. Vijaya Chaudhari.JR-3,Dept. of Pharmacology,Government Medical College, Nagpur.