In modern times, when it’s difficult to directly investigate vast amounts of overall data (populations), “sample surveys” and “estimation” play crucial roles in statistics. This article explains what sample surveys and estimation are, how they are used, and the benefits of learning these techniques. 1. What are Sample Surveys and Estimation? A sample survey is a method of investigating a portion of the overall data (a sample) and, based on the results, understanding the characteristics and trends of the entire population. - Why are Sample Surveys Necessary? Investigating the entire population takes a lot of time and resources. Therefore, it is practical to infer the overall trends using a randomly selected subset of data. - Ensuring Representativeness The sample must be obtained using methods such as random sampling or stratified sampling to faithfully reflect the characteristics of the population. Estimation is the process of “guessing” the characteristics (mean, variance, ratio,...