confidence hypothesis · Lesson 1 of 12
Point vs Interval Estimates
Point Estimate
A point estimate is a single value used to estimate a population parameter. For example, x̄ is a point estimate for μ, and p̂ is a point estimate for p.
Interval Estimate
An interval estimate gives a range of plausible values for the parameter, along with a confidence level. It acknowledges sampling variability rather than pretending we know the parameter exactly.
General Form
Confidence Interval = point estimate ± margin of error
Example
A sample of 50 students has x̄ = 72. The point estimate of μ is 72. A 95% CI might be (69, 75), meaning we are 95% confident the true population mean is between 69 and 75.