RANDOM SAMPLING

 The certain branch of mathematics which is concerned with the collection and interpretation of numerical data collected from the samples is called 'Statistics'.

According to Ciccarelli, "A sample is a group of subjects selected from a larger population of subjects, usually selected randomly....."

Blalock in 1960, has categorized sampling into two methods: Probability Sampling Methods and Nonprobability Sampling Methods.

Firstly, Probability Sampling Method determines the probable chance of inclusion of every unit or individual within the sample.

Secondly, Nonprobability Sampling Method is that method which is unable to provide us with knowledge of probable chance of an unit or individual's inclusion within the sample.

RANDOM SAMPLING:

The core of Behavioral Science Experimentation is 'Predict and Control'. Predicting all the factors that will act as variables and manipulating or controlling them in the hope of eliciting the perfect responses as the outcome of the experiment is the 'ideal' condition. But, this surreal situation is hard to reach, as knowing all the variables is impossible and controlling them is more inhuman.

The concept of Randomization works as a boon to this situation. When all the units or individual of a certain Universe or Population has equal and independent chance of being selected, the varied characteristics are included within the sample, which counterbalances in the long run.

So, the concept of randomness is at the center of the new era behavioral science research.

SAMPLING WITH AND WITHOUT REPLACEMENT:

Suppose we are conducting sampling with the fish bowl method. There are total 100 pieces of paper within the bowl. The chance of the 1st person to get selected is 1/100th . If we remove the piece of paper and choose the 2nd person - the chance of his selection becomes 1/99th.

a) Selection of unit or individual from the source without returning the slip is sampling without replacement.

b) Selection of unit or individual from the source returning the slips every time they were taken out, is sampling with replacement.

It can be concluded that sampling is fetching a portion of the universe or population as a representative of the same. And, Random Sampling is simply selection of this portion in such a fashion so that every individual has an equal and autonomous chance to be a part of the sample. 

REFERENCES:

Kerlinger, F. N., & Lee, H. B. (1986). Foundations of behavioral research, Fort Worth. TX: Holt, Rinehart, Winston.

Quinton, S. (2015). Saundra K. Ciccarelli and J. Noland White, Psychology (/Global Edition).

Singh, A. K. (2015). Tests, measurements and research methods in behavioural sciences. Bharati Bhawan.