Statistics
Confidence Interval Calculator
Mean ± z·s/√n confidence interval.
Free to use — no sign-up or login.
Margin of error
Lower
Upper
Amortization schedule
| # | Date | Payment | Principal | Extra | Interest | Balance |
|---|---|---|---|---|---|---|
This free Confidence Interval Calculator covers Mean ± z·s/√n confidence interval.
Approximate CI for a mean with known z and sample SD. Related statistics tools sit beside How it works, with no account required.
Using the Confidence Interval Calculator
Mean ± z·s/√n confidence interval. Typical inputs are Sample mean, Sample SD, Sample size and z (1.96≈95%). How it works beside the form states the identity the Confidence Interval Calculator applies.
FAQ
How do I use the Confidence Interval Calculator?
Open the Confidence Interval Calculator, fill Sample mean, Sample SD, Sample size and z (1.96≈95%), and read the result. Enter Sample mean, Sample SD, Sample size, and z (1.96≈95%) for the Confidence Interval Calculator; use Sample size greater than zero and interpret z (1.96≈95%) as a z-score. The calculator reports Margin of error, Lower, and Upper: Approximate CI for a mean with known z and sample SD. The interval uses a z approximation, so small or nonrepresentative samples need extra care.
What formula does the Confidence Interval Calculator use?
The Confidence Interval Calculator uses the identity in How it works. In words: Enter Sample mean, Sample SD, Sample size, and z (1.96≈95%) for the Confidence Interval Calculator; use Sample size greater than zero and interpret z (1.96≈95%) as a z-score. The calculator reports Margin of error, Lower, and Upper: Approximate CI for a mean with known z and sample SD. The interval uses a z approximation, so small or nonrepresentative samples need extra care.