Comparing Means Using Adjusted Confidence Intervals

• Activity Number: 432
• Type: Contributed
• Date/Time: Tuesday, August 11, 2015 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistical Graphics
• Author(s): Kimihiro Noguchi* and Fernando Marmolejo-Ramos
• Companies: Western Washington University and Stockholm University
• Keywords: Confidence interval ; Visualization

Abstract

A statistical inference procedure where the equality of means can be checked by the overlap of two interval estimates is discussed. The widths of these two intervals are adjusted according to the equal confidence level criterion so that the non-overlap indicates a significant difference at a prespecified level. In other words, statistical inference may be checked accurately by eye using two intervals lined up side by side. Moreover, using appropriate transformations, each interval may be made range-preserving and the mean difference may also be represented in terms of convenient effect sizes. A simulation study and real-life application illustrate usefulness of the suggested procedure.