Confidence Interval Calculator

Switch between mean and proportion modes to estimate population parameters from sample data.

Inputs — Mean

Sample mean (x̄)

Standard deviation (σ or s)

Sample size (n)

Confidence level (%)

Common values: 90, 95, 99

Results — Mean

Standard error (SE)

Z critical value

Margin of error

Lower bound

Upper bound

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p-value Calculator

Free p-value calculator for z, t, χ², F and correlation. One-/two-tailed tests, α significance check, critical value & interpretation. Instant results with steps & PDF.

Confidence Interval Calculator

Inputs — Mean

Results — Mean

Inputs — Proportion

Results — Proportion

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