Probability and Non Probability Sampling
The following s are some of the considerations for the selection of probability an non probability sampling.
1.Sometimes probability considerations for the selection probability and non probability sampling: non response is quite high the use of probability sampling looses its significance and non probability sampling may be more appropriate.
2.When the inquiry is to given more objectivity and the accuracy of the investigation is to be ensured at some desired level and then the only alternative is probability sampling.
3.Since randomness is not involved in non probability methods an estimate of sampling errors cannot be made.
4. When there are constraints of time money and availability of appropriate sample frame then the only course is non probability sampling. Especially in situations where more resources are to be devoted for accurate collection of information then in selection of the sample units e, g, consumer preferences non probability sampling is more appropriate.
The overall choice between probability and non probability sampling methods is a difficult is difficult exercise. The control and measurement of sampling error is probability sampling techniques should not be the sole determinant of sampling procedure. The final choice should depend on some informal judgment. The objectives of the inquiry the nature of the universe resources available at one disposal may be guiding factors in the selection or appropriate sampling methodology.