Producing data is a first step in four-steps process data.
In this step, we choose a individuals that included in the sample from population. We collect data from individuals to move EDA.
In this step have 2 stage:
- Sampling
- Study design
Sampling
In previous section, we said to sampling is a first stage in Producting data. Purpose of sampling is collect right data to statistics and conclude. If you don’t complete this stage or get bias data, we can waste time to do another step because the answer lead to invalid information. Be careful!
Types of sampling
- Volunteer sample, which individuals have selected themselves to be included, cannot generalize to any larger group at all
- Convenience sample, which individuals happen to be at the right time and place to suit the schedule of researcher.
- Systematic sample, which use many method to select individuals, such as Simple random sampling, Cluster sampling, Stratified sampling, …
We also learn various techniques by which one choose sample of inviduals from an entire population to collect data. This step is effect another step in process that we be careful in method selection.
Designing Studies
Obviously, sampling isn’t enough to producting data. Design study is a step which gain information about the variables of interest from the sampled individuals.
We will discuss some design studies in below:
- Observational study, in which value of variables or variables of interest are recorded as they naturally occur, such as sample survey, …
- Experiment, in this case which the researchers take control variables to see how to affect the response variables.
