## Probability Sampling: Definition

Probability Sampling may be a sampling technique during which sample from a bigger population are chosen employing a method supported the idea of probability. For a participant to be considered as a probability sample, he/she must be selected employing a random selection.

The most important requirement of probability sampling is that everybody in your population features a known and an equal chance of getting selected. For instance, if you’ve got a population of 100 people every one would have odds of 1 in 100 for getting selected. Probability sampling gives you the simplest chance to make a sample that’s truly representative of the population.

Probability sampling uses statistical theory to pick randomly, little group of individuals (sample) from an existing large population then predict that each one their responses together will match the general population.

## Types of Probability Sampling

Simple sampling because the name suggests may be a completely random method of choosing the sample. This sampling method is as easy as assigning numbers to the individuals (sample) then randomly choosing from those numbers through an automatic process. Finally, the numbers that are chosen are the members that are included within the sample.

There are two ways during which the samples are chosen during this method of sampling: Lottery system and using number generating software/ random number table. This sampling technique usually works around large population and has its justifiable share of benefits and drawbacks.

Stratified sampling involves a way where a bigger population is often divided into smaller groups that sometimes don’t overlap but represent the whole population together. While sampling these groups are often organized then draw a sample from each group separately.

A common method is to rearrange or classify by sex, age, ethnicity and similar ways. Splitting subjects into mutually exclusive groups then using simple sampling to settle on members from groups.

Members in each of those groups should be distinct in order that every member of all groups gets civil right to be selected using simple probability. This sampling method is additionally called “random quota sampling”

Cluster sampling may be thanks to randomly select participants once they are geographically opened up. For instance, if you wanted to settle on 100 participants from the whole population of the U.S., it’s likely impossible to urge an entire list of everyone. Instead, the researcher randomly selects areas (i.e. cities or counties) and randomly selects from within those boundaries.

Cluster sampling usually analyzes a specific population during which the sample consists of quite a couple of elements, for instance, city, family, university etc. The clusters are then selected by dividing the greater population into various smaller sections.

Systematic Sampling is once you choose every “nth” individual to be a neighborhood of the sample. For instance, you’ll choose every 5th person to be within the sample. Systematic sampling is an extended implementation of an equivalent old probability technique during which each member of the group is chosen at regular periods to make a sample. There’s an civil right for each member of a population to be selected using this sampling technique.

## Probability Sampling Example

Let us take an example to know this sampling technique. The population of the US alone is 330 million, it’s practically impossible to send a survey to each individual to collect information but you’ll use probability sampling to urge data which is nearly as good albeit it’s collected from a smaller population.

For example, consider hypothetically a corporation has 500,000 employees sitting at different geographic locations. The organization wishes to form certain amendment in its human resource policy, but before they roll out the change they want to understand if the workers are going to be proud of the change or not. However, it’s a tedious task to succeed in bent all 500,000 employees. this is often where probability sampling comes handy. A sample from the larger population i.e from 500,000 employees is often chosen. This sample will represent the population. A survey now is often deployed to the sample.

From the responses received, management will now be ready to know whether employees therein organization are happy or not about the amendment.

## What are the steps involved in Probability Sampling?

1. Choose your population of interest carefully: Carefully think and choose between the population, people you think that whose opinions should be collected then include them within the sample.

2. Determine an appropriate sample frame: Your frame should include a sample from your population of interest and nobody from outside so as to gather accurate data.

3. Select your sample and begin your survey: It can sometimes be challenging to seek out the proper sample and determine an appropriate sample frame. albeit all factors are in your favor, there still could be unforeseen issues like cost factor, quality of respondents and quickness to reply . Getting a sample to reply to true probability survey could be difficult but not impossible.

But, in most cases, drawing a probability sample will prevent time, money, and tons of frustration. You almost certainly can’t send surveys to everyone but you’ll always give everyone an opportunity to participate, this is often what probability sample is all about.

## When to use Probability Sampling

1. When the sampling bias has got to be reduced: This sampling method is employed when the bias has got to be minimum. The choice of the sample largely determines the standard of the research’s inference. How researchers select their sample largely determines the standard of a researcher’s findings. Probability sampling results in higher quality findings because it provides an unbiased representation of the population.

2. When the population is typically diverse: When your population size is large and diverse this sampling method is typically used extensively as probability sampling helps researchers create samples that fully represent the population. Say we would like to seek out what percentage people prefer medical tourism over getting treated in their own country, this sampling method will help pick samples from various socio-economic strata, background etc to represent the larger population.

3. To make an accurate sample: Probability sampling help researchers create an accurate sample of their population. Researchers can use proven statistical methods to draw accurate sample size to obtained well-defined data.