Statistical Inference
Point Estimate
A point estimate is a single best-guess number for an unknown population quantity, computed from your sample. If you survey 1,000 people and 530 say yes, your point estimate of the population proportion is 0.53.
A point estimate alone is dangerously incomplete because it hides uncertainty: 0.53 from 1,000 people and 0.53 from 10 people are wildly different in trustworthiness. That is why a point estimate should almost always travel with a standard error (標準誤) or a confidence interval (信賴區間) attached.
Sample mean income of $52,300 is a point estimate of the population’s mean income.