Snowball Sampling

Sometimes researchers need to study a group of population where identifying or finding potential subjects can be difficult because they are either deviant or socially isolated e.g. homeless people, drug addicts, members of an elite golf club etc.

Politically Important Cases Sampling

Politically important cases sampling is a type of Purposive Sampling where the sampling method attracts or avoids attracting attention undesired attention by including or eliminating specific sensitive samples.

Parallelogram Law of Vector Addition

Statement of Parallelogram Law If two vectors acting simultaneously at a point can be represented both in magnitude and direction by the adjacent sides of a parallelogram drawn from a point, then the resultant vector is represented both in magnitude and direction by the diagonal of the parallelogram passing through that point.

Triangle Law of Vector Addition

Statement of Triangle Law If 2 vectors acting simultaneously on a body are represented both in magnitude and direction by 2 sides of a triangle taken in an order then the resultant(both magnitude and direction) of these vectors is given by 3rd side of that triangle taken in opposite order.

Difference of Sets

The difference of set B from set A, denoted by A-B, is the set of all the elements of set A that are not in set B. In mathematical term, A-B = { x: x∈A and x∉B}

Basic Terminologies used in Sampling

Learning about any subject requires you to learn about the terminologies used in that subject. Sampling also has some technical terminologies that you should understand before you can start understanding the various sampling techniques and their advantages.

Non-Probability Sampling

We use Sampling techniques to reduce the time, money and other resources to be invested for our survey. Probability Sampling techniques are widely used in surveys for fair and unbiased sampling process. In some cases, the randomness of Probability Sampling can not address the niche need of the surveyors. In this case, we use Non- Probability Sampling.

Purposive Sampling and its Types

When choosing the method of sampling, we usually try to make sure that the samples represent the general population. But there are some cases where we might need an inquiry on certain items that fulfill specific criteria. This is where purposive sampling is useful. In purposive sampling, the items are selected in such manner that each of them are rich in information about the parameters that we are trying to study in the population.

Binomial Theorem and Expansion of Binomial Expression

The expression consisting of two terms is known as binomial expression. For example, a+b x+y Binomial expression may be raised to certain powers. For example, (x+y)2 (a+b)5 Expansion of Binomial Expression In order to expand binomial expression, we use repeated multiplication. For example,

Quota Sampling

Sampling is the process of selecting a subset of the population for analysis to save time and resources. In some cases, the properties or preferences of the population is determined by certain characteristics that puts them in certain groups e.g. the preference of clothes depends on age is different for children, teenagers, college students and working professionals.