what's the differnce between a population and a sample?

Question

give an example pls.

Answer 1

Sample is a subset of population.

10,000 prisoners from 10 different prisons across the USA; 20% make parole in a given year. That's 2,000 prisoners on parole (your population) and you want to study the rate of residivism in those prisoners who have made parole. Your sample size could be, say, 200. You track and study the sample as a way to extrapolate and generalize about the population.

Answer 2

A sample can be the same as the population, say everyone in your statistics class. However, lets say you want to know how many people in your school have red hair. The entire student body is the population, and you choose 100 students at random as the sample. You then determine how many people within this sample of 100 have red hair, and estimate the number of students in the entire student body, the population, who have red hair by applying the sample size over red hair frequency percentage you found in the sample of 100 to the population.

5 students out of 100, 5%; .05 x 1200 (the population-the student body) = 60.

Answer 3

The simplest distinction between the two can be stated by saying that a sample is a smaller set of something you are taking from a larger set of something (i.e., a population). This definition gets slightly more complicated when you begin to talk about the characteristics of your sample, since it makes the definition of population more complicated. This makes sense if you have ever conducted a research study.

If you have ever done a research study, the majority of the time, you are studying a sample consisting of individuals who have specific characteristics. Ideally, the sample should have characteristics as similar as possible to the population for which you would like to generalize your research results. (The concept of generalizability--to what degree does ones research say anything about people in general-- is strongly connected to the notions of sample and population).

Say for example, you are researching the study habits of grade 12 students. You obtain your sample from high school X. Depending on the characteristics of your sample, the definition of the population could be any number of things. As an example, if your study involves 40% of grade 12 students from high school X, the population could be all grade 12 students from high school X. However, if that sample consisted only of female students, then the appropriate population would be all female grade 12 students from high school X. The same thing would also occur if there are biases as they pertain to age, race, socioeconomic status, etc.

So the slightly more complex definition is that the characteristics of your study sample (in terms of age, race, socioeconomic status, etc.) dictates what the appropriate population reference (for which to generalize the results of a study) would/should be.

Answer 4

You walk into california. You wanna ask every californian whether they eat apple for breakfast ..... but you cant because there are millions of them and there are some who wont talk to you.

So, you devise a plan. You open up a phone directory and start calling every fifth name that you come across.

In this scenario, population = the actual people you want to know about. In this case, ALL californians.

Sample = a smaller part of the population whom you'd approach to ask / test your question. They (the sample) represesnt the population. The larger your sample, the more it is likely to represent the actual population.

Answer 5

Population is the entire unit or group which we have to study.
Sample is just a part of population which we study.
Though we ultimately study the total population only But sometimes its very difficult to study it coz there r so many units in it.......and it may consume time and lot many other thgs.So we take a sample from that poulation n study it and based on it we give the results for the entire population

Answer 6

The best way to think about this is:

Population - Is the ENTIRE set.
Sample - Is a portion of that set (meeting specific criteria)

Example:
You have a population of apples in the orchard (all the apples). The sample of that population could be the green apples.

Answer 7

a population is a collection of people... a sample is a smaller group of people chosen from the population to hopefully represent the group. Samples are usually taken because it is not possible to gather data from the entire population.

Answer 8

population refers to the entire universe.. that is when you are conducting a random experiment, and you take the entire population for the experiment, it means that you have to consider each and every element.
whereas a sample is a part of a population ie all the elements are not considered.

Answer 9

The population is referring to the actual amount of persons living in a certain demographic area. Whereas, "sample" refers to the amount of people that were actually surveyed in that same demographical area, which represents a fraction of that population.