The Reanalysis of the Donation Data Using the Zero-Inflated Possion Regression

- Journal title : Korean Journal of Applied Statistics
- Volume 22, Issue 4, 2009, pp.819-827
- Publisher : The Korean Statistical Society
- DOI : 10.5351/KJAS.2009.22.4.819

Title & Authors

The Reanalysis of the Donation Data Using the Zero-Inflated Possion Regression

Kim, In-Young; Park, Tae-Kyu; Kim, Byung-Soo;

Kim, In-Young; Park, Tae-Kyu; Kim, Byung-Soo;

Abstract

Kim et al. (2006) analyzed the donation data surveyed by Voluneteer 21 in year 2002 at South Korea using a Poisson regression based on the mixture of two Poissons and detected significant variables for affecting the number of donations. However, noting the large deviation between the predicted and the actual frequencies of zero, we developed in this note a Poisson regression model based on a distribution in which zero inflated Poisson was added to the mixture of two Poissons. Thus the population distribution is now a mixture of three Poissons in which one component is concentrated on zero mass. We used the EM algorithm for estimating the regression parameters and detected the same variables with Kim et al`s for significantly affecting the response. However, we could estimate the proportion of the fixed zero group to be 0.201, which was the characteristic of this model. We also noted that among two significant variables, the income and the volunteer experience(yes, no), the second variable could be utilized as a strategric variable for promoting the donation.

Keywords

EM algorithm;mixture of Poisson distributions;number of donations;zero inflated Poisson(ZIP);

Language

Korean

Cited by

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