What is Sampling?
According to Baraceros
(2016), it is a "method or process of selecting respondents or people to answer questions meant to yield data for a research study."
Types of Sampling
1. Probability Sampling - Probability Sampling is a sampling technique in which samples from a larger population are chosen using a method based on the theory of probability. For a participant to be considered as a probability sample, he / she must be selected using a random selection. (Bhat, 2019)
2. Non Probability sampling - Non-probability sampling is a sampling technique where the samples are gathered in a process that does not give all the individuals in the population equal chances of being selected.
Types of Probability Sampling
1. Simple random sampling- is a subset of a statistical population in which each member of the subset has an equal probability of being chosen.
Ex. Write names in paper, fold, put in a box, then randomly select the name
2. Systematic sampling- is a method in which sample members from a larger population are selected according to a random starting point and a fixed, periodic interval.
Ex. Population = 500; sample size- 50; get the every 10th person on the list
3. Stratified sampling- is a type of sampling method in which the total population is divided into smaller groups or strata to complete the sampling process.
Ex. Population = 500, sample size = 50, group the population by age, then get the sample by age.
4. Cluster Sampling- sampling method where multiple clusters of people are created from a population where they are indicative of homogeneous characteristics and have an equal chance of being a part of the sample.
Ex. Population = 500, sample size = 50, group the population by age, then get the sample of ages. Then you can perform SRS in to that group.
How to compute sample size
• Use SLOVIN’S FORMULA
Population = 1000; Confidence Level = 95%
or error = 5% or 0.05
n = 1000 / [1 + 1000 (0.05) 2 ]
= 1000 / [1 + 1000 (0.0025)]
= 1000 / (1 + 2.5)
= 1000 / 3.5
= 285.71 or 286
Non-Probability Sampling
1. Quota Sampling- non-probability sampling technique wherein the assembled sample has the same proportions of individuals as the entire population.
2. Voluntary Sampling -sampling in which people volunteer to participate in a survey.
3. Purposive Sampling- is one that is selected based on the characteristics of a population and the purpose of the study.
4. Availability Sampling- . It involves selecting a sample from the population because it is accessible.
5. Snowball Sampling- where research participants recruit other participants for a test or study.
Below is the video presentation of Sampling in Research
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