gives a confidence interval for the difference between the population means estimated from and .
- To use , you first need to load the Hypothesis Testing Package using Needs["HypothesisTesting`"].
- gives a confidence interval centered at Mean[list1]-Mean[list2].
- 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:
ConfidenceLevel 0.95 probability associated with a confidence interval EqualVariances False whether the unknown population variances are assumed equal KnownVariance None list of variances of each population