What is the Difference between Population and Sample? Individuals frequently need to judge the difference between population and sample.
Yet it is crucial in every statistical study, starting with descriptive statistics and varying variance and standard deviation calculations depending on whether we deal with a sample or a population.
Moreover, inferential statistics is sometimes referred to as the science of drawing inferences about a population using data collected on a sample that is typical of that community. Hence, making a clear distinction between the two ideas is essential.
What is the precise difference between a population and a sample? Let us further understand it from professional academic researcher Mr. Rashford works for UK Dissertation Services.
The key difference between population and sample in research
Population vs Sample
A population comprises all individuals that belong to a particular group, as well as any exciting results or data.
The specifications of the investigation will determine the specific population. Let us say, for example, that you are curious to know if job performance and the number of hours worked each week remotely correlate, especially in the Belgian case. Let us distinguish between population and sample.
In this case, Belgian data scientists may be the population. The population will be more targeted and only include personnel who meet the criteria if the study’s focus is more narrowly defined (for example, on Belgian data scientists who speak French and live 30 km away from their place).
Hence, it is essential to keep in mind that the population should only include people to whom the results will apply.
The population is the group from which specific observations are made. The sample is the set of components that participated in the investigation.
The terms “members” and “elements” are defined broadly. It may be a person. As an illustration, the sample might be “some individuals living in Belgium,” while the population may be “all people living in Belgium.” It might also be anything else.
Consider that you are examining how a new fertiliser would affect agricultural productivity. The ten crop fields you evaluated correlate to your sample, whereas all the agrarian fields represent your population. A sample is always smaller than the population since it is a subset of the population.
Remember that a population does not necessarily need to be significant. It is possible that the population you investigate is actually relatively tiny since it is so specific
(For example, first-year male bachelor students from your university who passed the statistics test in June and whose parents have been divorced for more than five years).
Why a sample?
Making inferences about a population from a representative sample is one of the major issues in statistics, as was indicated at the beginning of this article. Why not use the entire population instead of just a sampling of it? Measurements for the total research population are often nearly never achievable because:
- Too many individuals are present. Think about the number of expecting mothers. Every pregnant woman on the earth would likely take too long or cost too much to measure.
- There is a population virtually. In this context, “virtual population” refers to an unlimited “hypothetical” population. For example, we use individuals with prostate cancer to get a new treatment in an exploratory study.
The population varies, is now indeterminate and uncountable, and is thus virtual because we do not know how many individuals will receive therapy.
- The population is hard to reach. Using the number of homeless persons in Belgium as an example.
Due to these factors, measurements are done on a sample of our population or a subset of observations from the population.
The conclusions regarding the target population are then reached using these metrics. The findings acquired on a sample are frequently virtually as accurate as those that would be obtained on the entire population when the methodology is acceptable and the sample size is large enough.
Of course, the sample should be chosen to reflect the population being studied. There is a considerable risk that the study’s sample may not represent the population if individuals are enrolled voluntarily.
A selection bias may occur because of volunteers’ differences in the parameter2 of interest. Another example of selection bias is when a researcher uses the internet to gather citizen salaries. Those with internet access may make a different salary from those without.
The gold standard for selecting a sample representative of the investigated population is selecting a random sample. A random sample is one that is selected from the population at random, providing each candidate an equal chance of selection. A random sample is frequently an objective sample, which means that its unpredictable nature cannot be disputed.
The process of gathering a random sample of the population might be difficult or even impossible in specific circumstances or fields (such as medicine, psychology, etc.). In these situations, it will be crucial to take into account how representative the final sample will be.
Last but not least, paired samples are samples when groups (usually pairs) of experimental units are subjected to the same experimental settings.
For instance, one may count the hours that 20 patients slept (creating sample A) and then count the hours that those same patients slept once more after taking a sleeping medication (forming sample B).
The results of 25 students on the statistics and economics exams provide another example. It is clear that each student’s grades for these two examinations are somewhat connected to one another.
When a variable of interest is monitored on the same experimental unit at several intervals, paired samples are often created. Therefore, even when measurements are taken at a precise moment, paired samples might still exist.
For instance, suppose we gauged the strength of 30 athletes’ right and left arms. Samples A (for the right arm) and B (for the left arm) are paired samples because the strength in the right and left arms of the same person is related to one another.
The two samples and the two measures for each person are connected, whether it be hours of sleep before and after taking sleeping medication, grades on two distinct tests, or arm strength on the right and left. Statistical procedures that account for a relationship between the samples should be selected in that situation.
In conclusion, we can say that the population is the larger part to which we apply the following results. However, the sample is a subset of this study.
Now measuring the whole population is too difficult or impossible; inferences about the population are made using representative samples. The most representative samples are frequently those derived from random sampling.
Hopefully, you have understood Difference between Population and Sample in terms of research.