Two small-sample tests for random coefficients in linear regression are derived from the Maximum Likelihood Ratio. The first test has previously been proposed for testing equality of fixed effects, but is here shown to be suitable also for random coefficients. The second test is based on the...

In this paper it is illustrated, in a practical way, the use of three tools that permit the actuary to define tariff groups and to estimate risk premiums in the class-rating process for non-life insurance. The first is the segmentation analysis (CHAID and XAID) used firstly at 1997 by UNESPA in...

Some unit root testing situations are more difficult than others. In the case of quarterly industrial production there is not only the seasonal variation that needs to be considered but also the occasionally breaking linear trend. In the current paper we take this as our starting point to...

This Phillips-Ouliaris (1988) non-parametric unit root test for non seasonal data and the seasonal one of Joyeux (1992) are based in the estimation of the spectral density function in a fixed frequency. We can get consistent estimations of the spectrum using spectral windows, but such procedure...

Empirical studies have shown little evidence to support the presence of all unit roots present in the filter in quarterly seasonal time series. This paper analyses the performance of the Hylleberg, Engle, Granger and Yoo (1990) (HEGY) procedure when the roots under the null are not all present....

Several unit root tests in panel data have recently been proposed. The test developed by Harris and Tzavalis (1999 JoE) performs particularly well when the time dimension is moderate in relation to the cross-section dimension. However, in common with the traditional tests designed for the...

The lack of suitable critical values for the Dickey-Fuller integrability test in finite-samples can drive researchers to spurious conclusions when using asymptotic critical values. In this paper we estimate response surfaces for the Dickey-Fuller unit root test with structural breaks that allow...

This paper proposes a test statistic for the null hypothesis of panel stationarity that allows for the presence of multiple structural breaks. Two different specications are considered depending on the structural breaks affecting the individual effects and/or the time trend. The model is exible...

The paper addresses the concept of multicointegration in panel data frame- work. The proposal builds upon the panel data cointegration procedures developed in Pedroni (2004), for which we compute the moments of the parametric statistics. When individuals are either cross-section independent or...

In the present paper we study the effects in econometric inference when ussing seasonal adjusted data obtained by signal extraction filters. In particular we analyze the effects in the integration order in zero frequency of the adjusted series. We center our study in the consequences of the...