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Free Confidence Interval
Calculator

Calculate confidence intervals for a mean with t or z, a population proportion with Wilson score, raw datasets, or a difference of two independent means using Welch

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About Free Confidence Interval Calculator

Build confidence intervals with the model that matches your data: Student-t for an unknown population SD, z when σ is known, Wilson score for a proportion, raw-data t intervals, or Welch intervals for two independent means.

Available actions

  • Raw data
  • Mean · t
  • Mean · known σ
  • Proportion · Wilson
  • Two means · Welch
  • Calculate interval