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Estudo

Testing covariance stationarity

Xiao, Zhijie; Lima, Luiz Renato Regis de Oliveira

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Resumo

In this paper, we show that the widely used stationarity tests such as the KPSS test have power close to size in the presence of time-varying unconditional variance. We propose a new test as a complement of the existing tests. Monte Carlo experiments show that the proposed test possesses the following characteristics: (i) In the presence of unit root or a structural change in the mean, the proposed test is as powerful as the KPSS and other tests; (ii) In the presence a changing variance, the traditional tests perform badly whereas the proposed test has high power comparing to the existing tests; (iii) The proposed test has the same size as traditional stationarity tests under the null hypothesis of stationarity. An application to daily observations of return on US Dollar/Euro exchange rate reveals the existence of instability in the unconditional variance when the entire sample is considered, but stability is found in subsamples.

Ficha do documento

Tipo
Estudo
Ano
2006
Instituição
Escola de Pós-Graduação em Economia da FGV
Idioma
Inglês
Acesso
Não informado
Identificador
oai:repositorio.fgv.br:10438/948

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