🔥 Free Chi-Square Calculator – Test of Independence
Confidence Interval Calculator
Calculate the Confidence Interval, Margin of Error, and Standard Error for sample means or sample proportions instantly.
Confidence Level
Sample Size (n)
Sample size must be greater than 1.
Sample Mean (x̄)
Standard Deviation (s)
Standard Deviation cannot be negative.
Sample Proportion (p̂)
Proportion must be between 0 and 1.
Confidence Interval (95%)
[ 48.040 , 51.960 ]
48.040
Lower Bound
51.960
Upper Bound
Margin of Error (E)
± 1.960
Z-Scores & Formulas
90% ConfidenceZ = 1.645
95% ConfidenceZ = 1.960
99% ConfidenceZ = 2.576
Formula (Mean)
CI = x̄ ± Z * (s / √n)
This calculator uses Z-distribution assuming sample size n ≥ 30 or known population standard deviation. Calculations are processed locally.
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