What is Census
collecting information from every single person or item in the whole group you’re studying, not just a part of it
What is Sample
Subgroup of the elements of the population selected for participation in the study
Sampling design process
Define the target population
Select sampling techniques
Define the sample size
Execute the sampling process
Define the target population
The target population should be defined in terms of elements, sampling units, extent, time
What is Element in terms of Target population
the object about which or from which the information is desired, e.g., the respondent.
What is Nonprobability Sampling
You don’t know everyone’s chance of being chosen - you just pick people who are easy to reach or available
What is Probability Sampling
Everyone in the group has a known and fair chance to be chosen - like picking names from a hat
What are Probability Sampling Techniques are there
Simple Random, Systematic, Stratified, Cluster
What is sampling unit in terms of target population
where you select your sample from — it’s the source or group that contains the elements
Eg. If you want to study people working at Google,
→ Google company is your sampling unit,
→ and each employee is the element
What is extent in terms of target population
Geographic boundaries
What Sampling Techniques are there
Nonprobability and Probability Sampling Techniques
What is Nonprobability Samples
not everyone has a known or equal chance to be chosen. The researcher picks people based on convenience or judgment, so it’s quicker and easier, but the results might not represent everyone.
What is Simple random
The probability of being selected into a sample is equal for all the members of the population
What is Systematic Sampling
We select respondents at regular intervals from a list.
We choose a random starting point, and the picking every ith element. The sampling interval (i), population size (N), sample size (n). Equation i=N/n
What is Stratified Sampling
When the population is first divided into smaller groups called strata based on shared characteristics such as age, gender, income, or education. Then, a random sample is taken from each stratum. This helps make sure that all important groups are fairly represented in the final sample.
What is Cluster Sampling
used when the population is very large or spread out.
First, the population is divided into smaller groups called clusters - for example, schools, cities, or districts.
Then, some of these clusters are randomly chosen, and data is collected from them. Two types: One-stage and two-stage cluster sapling
What are the One-stage and Two-stage Cluster Samplings
One-stage cluster sampling: You randomly select some clusters and include everyone inside those clusters in your study.
Two-stage cluster sampling: You randomly select some clusters, but then you also randomly pick certain people within each chosen cluster.
What are Nonprobability Sampling Techniques
Convenience, Judgemental, Quota, Snowball Sampling
What is Convenience Sampling
When the researcher chooses people who are easy to reach or available at the moment.
It doesn’t give everyone in the population an equal chance to be chosen - only those who are convenient to contact.
What if Judgemental Sampling
where the researcher chooses people on purpose, based on their knowledge, experience, or importance to the study.
Instead of picking people randomly, the researcher uses their own judgment to decide who will give the most useful or relevant information.
What is Quota Sampling
When the researcher first divides the population into groups based on specific characteristics, such as age or gender. After setting the required number of participants for each group, the researcher then selects individuals conveniently or by judgment until each quota is filled. This ensures that key groups are represented, even though the selection within each group is not random.
What is Snowball Sampling
Initial group of responders is selected usually at random. After being interviewed, these respondents are asked to identify others who belong to the target population of interest.
