Table of Contents

## Population and Sample in Statistics

A population is the complete set of objects that you are interested in. A sample is a subset of the population.

In statistics, we often want to learn about the properties of a population by studying a sample. For example, we might want to know the average height of all adults in the United States. To measure this, we would take a sample of adults and calculate the average height for this group.

There are a few important things to keep in mind when working with samples:

1. A sample can never be identical to the population.

2. A sample is always smaller than the population.

3. A sample is not necessarily representative of the population.

4. The results of a study done on a sample can never be generalized to the population.

## What is the population?

The population is the number of people living in a certain area.

## Sample

The following is a sample explanation of an event.

The event could be anything, such as a party, a wedding, or a meeting.

The event took place on Saturday, December 5, 2009.

The event was a party held at the home of the bride and groom.

The party began at 7:00 p.m. and ended at 11:00 p.m.

The party was attended by 50 people.

The party was a great success!

## Probability sampling

is a sampling technique that takes into account the likelihood of each member of the population having an opportunity to be selected in the sample. Probability sampling is used when the population is known and the researcher wants to make sure that every member of the population has an equal chance of being selected in the sample.

There are a number of different types of probability sampling techniques, including:

random sampling

stratified sampling

cluster sampling

multistage sampling

proportional allocation

## Population and Sample Examples

There are about 7.5 billion people on Earth.

There are about 3.5 billion people who speak English.

## Population and Sample Formula

The population is the entire set of items or people that you are studying. The sample is a subset of the population. The population size is the total number of items or people in the population. The sample size is the number of items or people in the sample.