Learn in the textbookStatistical Analysis and Inference
DefinitionEstimation (推定) is a method of working out values such as the mean of the whole group you want to study (the population (母集団)) from data on a sample (標本), a part taken from that group.
ExplanationThere is point estimation (点推定), which gives a single value, and interval estimation (区間推定), which gives a range with a width. Interval estimation also states how likely it is that the population value falls in that range, as a confidence level (信頼度).
AnalogyIt is like tasting one spoonful of soup to judge how salty the whole pot is. The spoonful is the sample, and the whole pot is the population.
Memory hookThe Japanese word 推定 combines 推 (to infer) and 定 (to fix). You start from the part in hand and pin down a value for the whole.