Definition: The Central Limit Theorem states that when a large number of simple random samples are selected from the population and the mean is calculated for each then the distribution of these sample means will assume the normal probability distribution. In other words, the sample means will be normally distributed when the mean and standard deviation of the population is … [Read more...] about Central Limit Theorem

## Non-Sampling Error

Definition: The Non-Sampling Error is the statistical error that arises due to the factors other than the ones that occur when the inference is drawn from the sample. Simply, the errors caused due to the defective methods of data collection, faulty definition, incomplete population coverage, wrong tabulations, etc. when the complete enumeration of all the items in the … [Read more...] about Non-Sampling Error

## Sampling Error

Definition: The Sampling Error refers to the statistical error occurred when the subset of the population (sample) deviates from the true characteristics, attributes and behavior of the total population. Simply, when the sample selected from the population differs from the actual attributes of the target population, then the sampling error arises. Basically, there are two … [Read more...] about Sampling Error

## Snowball Sampling

Definition: The Snowball Sampling is a non-random sampling technique wherein the initial informants are approached who through their social network nominate or refer the participants that meet the eligibility criteria of the research under study. Thus, this method is also called as the referral sampling method or chain sampling method. The snowball sampling method is … [Read more...] about Snowball Sampling

## Convenience Sampling

Definition: The Convenience Sampling is the non-probability sampling technique wherein a proportion of the population is selected on the basis of its convenient availability. This method is also called the chunk (fraction) taken from the population on the basis of its convenient accessibility and availability to the investigator. The telephone directory, census survey … [Read more...] about Convenience Sampling

## Quota Sampling

Definition: The Quota Sampling is yet another non-probability sampling method wherein the population is divided into a mutually exclusive, sub-groups from which the sample items are selected on the basis of a given proportion. Simply, Quota Sampling is a form of judgment sampling technique wherein the investigator selects the sample items from the exclusive sub-groups on the … [Read more...] about Quota Sampling

## Judgement Sampling

Definition: The Judgement Sampling is the non-random sampling technique wherein the choice of sample items depends exclusively on the investigator’s knowledge and professional judgment. In other words, the investigator chooses only those sample items which he feels to be the best representative of the population with regard to the attributes or characteristics under … [Read more...] about Judgement Sampling

## Multistage Sampling

Definition: The Multistage Sampling is the probability sampling technique wherein the sampling is carried out in several stages such that the sample size gets reduced at each stage. The multistage sampling is a complex form of cluster sampling. The cluster sampling is yet another random sampling technique wherein the population is divided into subgroups called as clusters; … [Read more...] about Multistage Sampling

## Systematic Sampling

Definition: The Systematic Sampling is yet another probability sampling technique wherein the starting point from where the element is to be drawn from the population is chosen randomly and then the subsequent items are selected on the basis of the fixed periodic interval between the sample items. The systematic sampling is a periodical method wherein the sample members are … [Read more...] about Systematic Sampling

## Stratified Sampling

Definition: The Stratified Sampling is a sampling technique wherein the population is sub-divided into homogeneous groups, called as ‘strata’, from which the samples are selected on a random basis. The strata are formed on the basis of the member’s shared attributes and characteristics. These are mutually exclusive as every item of the population is assigned to a single … [Read more...] about Stratified Sampling