The Importance Of Sample Surveys

Overview

Sample surveys are based on data recorded for a subset of the population, the sample, and are intended to draw conclusions about unknown population parameters. Sampling methods are divided into probability sampling and non-probability sampling. For samples selected according to a probability method, it is possible to draw conclusions and extend it to the population using Statistical Inference. For data collected in a non-probability sample, it is possible to apply descriptive statistics to present the results of the survey, but it cannot be extended to the population.

In summary, Sampling Theory is the field of statistics that includes the methodology (a) for selecting a sample from a larger population and (b) to derive reliable conclusions

These data come from or relate to issues around every aspect of our personal, social or professional life. The large volume of data makes it necessary to express them with quantitative data and graphs in order to better organize, present and understand them, and draw conclusions. The need for quantitative conclusions on everyday issues is the subject of sampling. The need to quickly extract results and to compare them at regular intervals makes the use of sampling investigations necessary in relation to the alternative that is population census. In the following section, the definitions of population, inventory and sample are given in

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Sample Selection Steps in Simple Random

The implementation of a simple random sampling is performed as follows:

1. We assign each unit of the population with a number from 1 to N

2. With a random number process (computer or random number tables), we select a set of random numbers. These numbers should be distinct (not equal) and smaller of N

3. The population units corresponding to the random numbers generated in accordance with the assignment are selected for the sample

Simple Random Example

In primary school clash of 30 students, a sample survey will be carried out to assess the number of children who have not made the primary vaccines.

Suppose that in the research we intend to choose a sample of 5 children. To select the sample, a number from 1 to 30 is initially assigned to each student. Then five random numbers are selected.

Stratified