is a foundational concept in inferential statistics used to estimate population parameters from sample data. Instead of providing a single point estimate (like just a mean), a confidence interval (CI) provides a range of values where the true population parameter is likely to lie. What is a Confidence Interval?
A confidence interval estimates the of an observation. For example, a 95% CI means that if you were to repeat the same study multiple times with new samples, the true population value would fall within your calculated intervals 95% of the time.
: Often set at 90%, 95%, or 99%. A higher level (e.g., 99%) creates a wider, more inclusive interval.