Math & Statistics
Confidence Interval Calculator
Find the confidence interval for a sample mean.
Your inputs
Change any value to update the result instantly.
Margin of error
4.1577
Lower bound
95.8423
Upper bound
104.1577
Z-score
1.96
Formula and working
CI = x̄ ± z·(σ ÷ √n)
- 1
Collect the inputs
Sample mean = 100; Standard deviation = 15; Sample size = 50; Confidence level = 95
- 2
Apply the formula
CI = x̄ ± z·(σ ÷ √n)
- 3
Result
Margin of error = 4.1577
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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