gives a confidence interval for the difference between the population means estimated from and .


  • To use MeanDifferenceCI, you first need to load the Hypothesis Testing Package using Needs["HypothesisTesting`"].
  • MeanDifferenceCI[list1,list2] gives a confidence interval centered at Mean[list1]-Mean[list2].
  • MeanDifferenceCI is based on a normal distribution if the population variances are assumed known.
  • If the variances for the two populations are assumed equal and unknown, the interval is based on Student's distribution with Length[list1]+Length[list2]-2 degrees of freedom.
  • If the population variances are not assumed known and not assumed equal, Welch's approximation for the degrees of freedom is used.
  • The following options can be given:
  • ConfidenceLevel0.95probability associated with a confidence interval
    EqualVariancesFalsewhether the unknown population variances are assumed equal
    KnownVarianceNonelist of variances of each population
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