Research concepts
Prediction Intervals and Confidence Intervals
Prediction and confidence intervals: Does the interval concern a parameter or a new observation?
Source editorial review:
Before interpreting the result
Does the interval concern a parameter or a new observation?
- Record the estimated object and the interval's stated level.
- Distinguish parameter uncertainty from variability in future observations.
- Keep the population, model and assumptions delimiting interpretation.
Prediction and confidence intervals
Interpret an interval according to the quantity it targets. A confidence interval for a parameter and a prediction interval for a new observation answer different questions. Both depend on models, data and assumptions; comparing widths without identifying their target can mislead about precision or variability.
A reading case: what to check
If a report shows a band around a line, read its legend before treating it as the expected range of future samples. Record interval type, level and target. Where that information is absent, do not turn the band into a batch tolerance. Statistical margins and documentary acceptance criteria require different justifications.
What to preserve in the record
Do not use a confidence interval for a mean as the expected range of every future sample. Keep the interval's name beside its numerical limits.
Questions and answers
Does the interval concern a parameter or a new observation?
Interpret an interval according to the quantity it targets. A confidence interval for a parameter and a prediction interval for a new observation answer different questions. Both depend on models, data and assumptions; comparing widths without identifying their target can mislead about precision or variability.
What should the review record preserve?
Do not use a confidence interval for a mean as the expected range of every future sample. Keep the interval's name beside its numerical limits.