Confidence Interval Calculator
About Confidence Interval Calculator
Estimate a confidence interval for a sample mean with z or t assumptions.
How to Use
Estimate a confidence interval for a sample mean with z or t assumptions. Fill in Sample mean, Sample standard deviation, Sample size, Confidence level, and Interval method, then review the calculated Margin of error, Lower bound, Upper bound, Critical value, Standard error, and Assumption.
- Open the calculator : Use Confidence Interval Calculator from the Math category.
- Check the inputs : Review the required values and any optional settings.
- Read the formula : Use the formula and notes below to understand how the result is produced.
Common Questions
What formula does the Confidence Interval Calculator use?
Margin of error = critical value × standard error, where standard error = sample standard deviation / ?(n). Interval = mean ± margin of error.
Inputs
- Sample mean
- Sample standard deviation
- Sample size
- Confidence level
- Interval method
Outputs
- Margin of error
- Lower bound
- Upper bound
- Critical value
- Standard error
- Assumption
Formula
Margin of error = critical value × standard error, where standard error = sample standard deviation / sqrt(n). Interval = mean ± margin of error.