Abstract
It is known that in the critical case the conditional least squares estimator (CLSE) of the offspring mean of a discrete time branching process with immigration is not asymptotically normal. If the offspring variance tends to zero, it is normal with normalization factor n2 / 3. We study a situation of its asymptotic normality in the case of non-degenerate offspring distribution for the process with time-dependent immigration, whose mean and variance vary regularly with non-negative exponents α and β, respectively. We prove that if β < 1 + 2 α, the CLSE is asymptotically normal with two different normalization factors and if β > 1 + 2 α, its limit distribution is not normal but can be expressed in terms of the distribution of certain functionals of the time-changed Wiener process. When β = 1 + 2 α the limit distribution depends on the behavior of the slowly varying parts of the mean and variance.
| Original language | English |
|---|---|
| Pages (from-to) | 1892-1908 |
| Number of pages | 17 |
| Journal | Stochastic Processes and their Applications |
| Volume | 118 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2008 |
Bibliographical note
Funding Information:This paper is based on a part of the results obtained under research project MS/THEOREM/335 funded by King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia. I am grateful to the referee and the associate editor for careful readings of the first version of the paper and for valuable comments.
Keywords
- Branching process
- Functional
- Least squares estimator
- Skorokhod space
- Time-dependent immigration
ASJC Scopus subject areas
- Statistics and Probability
- Modeling and Simulation
- Applied Mathematics