Saturday, January 21, 2023

Representative sample

A representative sample is a tiny amount or a subset of something larger, according to the definition. It exhibits the same characteristics and ratios as a bigger population.
Consider a company that is getting ready to introduce a new product in a US city, for instance. It will be nearly hard to send a survey to everyone in the city in order to get their opinions on the features of the product. To handle their comments on the product, researchers gather a small sample of people who will adequately represent the population of the city. We refer to this sample as a representative sample.

Researchers can generalize the knowledge they have gathered to a larger population when they use a representative sample. In terms of time, money, and resources, the majority of psychological and market research studies are inappropriate for gathering data on everyone. In particular, with a big population like a whole country, it is almost impossible to collect data from every single person.

Importance of a representative sample for studies in applied research
  • A representative sample will be helpful to you if you want to conduct market research that is effective.
  • A representative sample is a small group of individuals who as closely as possible represent a larger group. Then, using a sample of the population that we believe to be the most representative of our target group, we can conduct an online survey, for instance.
How to build a representative sample
  1. Probability sampling: This technique involves selecting a sample from a broader population using a procedure based on probability theory. Participant selection must be done at random for them to be regarded as a probability sample.
  2. Non-probability sampling is a sampling method in which the researcher chooses samples based on his or her personal assessment rather than through random selection. In contrast to probability sampling, which gives every member of the population a known chance of being chosen, non-probability sampling gives only some population members a chance of taking part in the study.
When a sample is not representative, we have a sampling error known as the margin of error. If we want a representative sample of 100 employees, we must select an equal number of men and women. For example, if we have a sample that is biased toward a specific genre, we will have a sample error.
The sample size is important, but it does not ensure that it accurately represents the population that we require. More than size, representativeness is linked to the sampling frame, or the list from which people are drawn, as in a survey. As a result, we must take care to include people from our target audience in that list in order to claim that it is a representative sample.

Friday, January 20, 2023

Random sampling and ways of obtaining a Random sampling

 Random sampling and ways of obtaining a Random sampling


Random sampling is a technique for selecting a sample of observations from a population in order to draw conclusions about the population. It is also known as probability sampling. Non-probability sampling or Non-random sampling is the opposite of this sample. Simple random sample, stratified sampling, cluster sampling, and multistage sampling are the main varieties of this sampling. Convenience samples are often known as non-arbitrary samples in sampling methodologies.
Probability sampling's key characteristic is that the selection of data must be 'random' in a way that prevents them from significantly diverging from unsampled observations. Here, we presume that the data used in statistical investigations was drawn using random sampling.

Type of Random Sampling

The random sampling technique makes use of a random selection in some way. In this strategy, everyone who qualifies can select a sample from the entire sample space. It is a costly and time-consuming approach. Utilizing probability sampling has the benefit of guaranteeing that the sample will accurately reflect the population. There are four main subtypes of this sampling technique:
  1. Simple Random Sampling
  2. Systematic Sampling
  3. Stratified Sampling
  4. Clustered Sampling
Simple random sampling
With this sampling technique, every component of the population has an equal and likely chance of being included in the sample (for example, each member in a group is marked with a specific number). This method is referred to as "Method of Chance Selection" since the choice of an item is entirely dependent on possibilities. Additionally, a large sample size was used, and a random object was chosen. The term "Representative Sampling" is a result.

Systematic Random Sampling
In this method, after a certain sampling period, the other methods are picked along with the random selection point to select the items from the target population. The ratio of the entire population to the necessary population size is what it is equal to.

Stratified Random Sampling
In this sampling technique, a population is broken down into smaller groups in order to collect a simple random sample from each group and complete the sampling procedure (for example, number of girls in a class of 50 strength). Strata are the collective nouns for these little groups. Several characteristics of the population are used to generate the tiny group. The researcher selects a sample at random after segmenting the population into smaller groups.

Clustered Sampling
The population is divided into a high number of subgroups in cluster sampling, unlike stratified sampling (for example, hundreds of thousands of strata or subgroups). After that, simple random samples are taken from some of these subgroups that were randomly selected. The term "clusters" refers to these subdivisions. Essentially, it is used to reduce the cost of data compilation.

Representative sample

A representative sample is a tiny amount or a subset of something larger, according to the definition. It exhibits the same characteristics...