Definition

According to William G. Cochran, sampling is “the process of selecting a subset of individuals from a population to estimate characteristics of the whole population.”

Introduction

Sampling is how marketers study a crowd without asking every single person. The trick lies in picking a small group that represents the big picture.

Explanation

1️⃣ Probability Sampling – each member has known chance of selection (random, stratified, cluster).
2️⃣ Non-Probability Sampling – convenience, judgmental, snowball.
3️⃣ Sample Size & Error – balance cost, confidence, and accuracy.

Key Takeaways

• Random sampling ensures objectivity.

• Large samples reduce error but increase cost.

• Representativeness is more important than size.

Real-World Case

Nielsen Ratings use representative TV households to estimate national viewing habits—proof of accurate sampling power.
Reference: https://www.nielsen.com