Artigo
Study of tests for trend in time series
Registro en:
PAIVA, D. de A.; SÁFADI, T. Study of tests for trend in time series. Brazilian Journal of Biometrics, [S. l.], v. 39, n. 2, p. 311-333, 2021. DOI: 10.28951/rbb.v39i2.471.
Autor
Paiva, Denise de Assis
Sáfadi, Thelma
Institución
Resumen
The time series methodology is an important tool when using data over
time. The time series can be composed of the components trend (Tt), seasonality (St)
and the random error (at). The aim of this study was to evaluate the tests used to
analyze the trend component, which were: Pettitt, Run, Mann-Kendall, Cox-Stuart and
the unit root tests (Dickey-Fuller, Dickey-Fuller Augmented and Zivot and Andrews),
given that there is a discrepancy between the test results found in the literature. The
four series analyzed were the maximum temperature in the Lavras city, MG, Brazil,
the unemployment rate in the Metropolitan Region of S˜ao Paulo (RMSP), the Broad
Consumer Price Index (IPCA) and the nominal Gross Domestic Product (GDP) of
Brazil. It was found that the unit root tests showed similar results in relation to the
presence of the stochastic trend for all series. Furthermore, the turning point of the
Pettitt test diverged from all the structural breaks found through the Zivot and Andrews
test, except for the GDP series. Therefore, it was found that the trend tests diverged,
obtaining similar results only in relation to the unemployment series.