JSM 2013 Home
Online Program Home
My Program

Abstract Details

Activity Number: 684
Type: Contributed
Date/Time: Thursday, August 8, 2013 : 10:30 AM to 12:20 PM
Sponsor: Biometrics Section
Abstract - #308746
Title: Two Group Comparisons Using Mean-Based Tests Derived from Zero-Inflated Gamma and Zero-Inflated Log-Normal Models
Author(s): Elizabeth Mills*+ and Jeffrey D. Dawson
Companies: Univerisity of Iowa and The University of Iowa
Keywords: semicontinuous data ; point-mass mixture data ; consonant tests ; two-part models ; regression
Abstract:

Positive continuous data with a point-mass at zero can be modeled via two-part models assuming distributions such as zero-inflated gamma and zero-inflated log-normal. The two parts model the probability of a nonzero outcome and the distribution of the nonzero outcomes. Many researchers have used these models making conclusions based on the two parts separately. This presentation explores methods of combining the two parts of these models. Specifically, tests are derived to compare the overall means of two groups using the difference of the overall group means and the ratio of group means. Simulation studies are used to explore the Type 1 error and power both when the models are correctly specified and when they are misspecified. The use of these mean-based tests will also be illustrated through data obtained through our collaboration work in the field of neurology.


Authors who are presenting talks have a * after their name.

Back to the full JSM 2013 program




2013 JSM Online Program Home

For information, contact jsm@amstat.org or phone (888) 231-3473.

If you have questions about the Continuing Education program, please contact the Education Department.

The views expressed here are those of the individual authors and not necessarily those of the JSM sponsors, their officers, or their staff.

ASA Meetings Department  •  732 North Washington Street, Alexandria, VA 22314  •  (703) 684-1221  •  meetings@amstat.org
Copyright © American Statistical Association.