Confidence Interval Calculator
Calculate confidence intervals for means, proportions, and differences
Calculator Mode
Confidence Level
Confidence Interval for Mean
About Confidence Intervals
A confidence interval gives a range of plausible values for a population parameter based on sample data.
Interpretation: If we repeated the sampling process many times, approximately 95% of the constructed intervals would contain the true population parameter.
When to use:
- Z-interval: Known population σ or large n (≥30)
- T-interval: Unknown population σ with small n
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