# What is the difference between Universe and Population?

On one hand, the universe contains "all the entities one wishes to consider in a given situation" on the other the population is "a set of similar items or events which is of interest for some question or experiment".

A co-worker said when she learned statistics they used the word universe; when I did we said population. Neither of us had heard of the other word. What if any is the difference?

I just took stats last year. Population is, as you described, a complete set of elements (persons or objects) that possess some common characteristic defined by the sampling criteria established by the researcher.

In statistics, Universe is a synonym of Population.

Source: population. (n.d.) Collins English Dictionary – Complete and Unabridged, 12th Edition 2014. (1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014). Retrieved October 20 2017 from https://www.thefreedictionary.com/population

Confirming the use of Universe and Population, as synonyms in modern data science:

https://stats.oecd.org/glossary/detail.asp?ID=2087

The term 'universe', while it has a well-established meaning in set theory and other related mathematical fields, in my experience is rarely used in statistics as a synonym of the term 'population'.

Indeed, all classical statistics textbooks, exclusively use the term 'population', usually defined as

entire group of individuals (not necessarily people) about which we want information.

On the other hand, the 'sample' can be defined to be

A sample is the part of the population from which we actually collect information. We use a sample to draw conclusions about the entire population.

Conceptually the two terms mean essentially the same thing, i.e. the set of all possible statistical units, but past statisticians decided to call this set 'population' so we adhere to this convention.

• Interesting you included set theory. Maybe this is the source of the confusion. I don't think universe and population should be used interchangeably in statistics. Commented Jul 6 at 20:16

The universe is broad in its nature. The universe in research is the area of your study while the population is the specific characteristics of the universe and the samples are selected units of the population.

• Regardless the use of the terms in different disciplines this definition actually takes into account the ordinary meaning of each of the words taking into account their different meanings. Can you please provide an example for each term according your definition? Commented Jul 6 at 20:15

The collection of all elements possessing common characteristics that comprise universe is known as the population. A subgroup of the members of population chosen for participation in the study is called sample. The population consists of each and every element of the entire group.

Universe is the set all experimental units, from which a sample is to be drawn. Population is the set of all values of the variables to be studied from those experimental units. Thus, a U-sample contains experimental units, whereas a P-sample contains data.

• Statistics are validly applied to study designs other than experimental study designs. Commented Feb 17, 2020 at 17:05

The collection of all elements possessing common characteristic that comprise (Univers) is known as the population.

And the subgroup of the member of population chosen for participating in the studybis called (Sample).

• This answer would be improved if it cited an authoritative source, such as a book, article, or other scholarly publication.
– Sycorax
Commented Feb 17, 2020 at 17:03