GNDU B.Com (Bachelor of Commerce)

Chapter 1: Introduction to Statistics and SamplingSemester 1 — summary, notes, extra questions & MCQ quiz

Summary

Statistics, in the plural sense, means numerical data, and in the singular sense it is the science of collecting, organising, presenting, analysing and interpreting such data to aid decision-making. In economics and business its scope is wide: it measures national income, prices, production, demand and supply, and helps in forecasting and planning. Its significance lies in presenting facts in definite form, simplifying mass data, facilitating comparison, studying relationships and helping policy formulation. However, statistics has limitations: it studies aggregates rather than individuals, deals only with quantitative (or quantified) facts, can be misused, and its results are true only on an average. A central idea is sampling, which studies a part of the whole to draw conclusions about the whole. Key concepts include the population or universe (the entire group under study), the sampling unit (each member that may be selected), complete enumeration or census (studying every unit), and the sample survey (studying a representative part). A good sample should be representative, adequate in size, free from bias and homogeneous in nature. Sampling techniques are broadly probability methods, such as simple random, stratified, systematic and cluster sampling, in which every unit has a known chance of selection, and non-probability methods, such as convenience, judgement and quota sampling, where selection depends on the investigator. Sampling saves time and cost and is often the only feasible method when the population is very large.

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