Book Reviews

Books reviewed:
David Griffiths, W. Douglas Stirling, and K. Laurence Weldon, Understanding Data: Principles and Practice of Statistics
Ingwer Borg and Patrick Groenen, Modern Multidimensional Scaling: Theory and Applications
Jeffrey H. Dorfman, Bayesian Economics Through Numerical Methods: A Guide to Econometrics and Decision-making with Prior Information
Marek Musiela and Marek Rutkowski, Martingale Methods in Financial Modelling: Theory and Applications
Aad W. van der Vaart and Jon A. Wellner, Weak Convergence and Empirical Processes     

The effects of testosterone deficiency on male sexual function

Introduction. Patients with late onset hypogonadism (LOH) also suffered from lower urinary tract symptoms (LUTS) and LOH symptoms. The objects of this study are to evaluate the efficacy of testosterone replace therapy (TRT) by testosterone ointment (Glowmin: GL) for LUTS in LOH patients.

Methods. The Aging Male Symptom (AMS) scale, Medical Outcomes Study (MOS) 36-Item Short-Form Health Survey (SF-36), International Index of Erectile Function (IIEF-5) and the International Prostate Symptom Score (IPSS) were obtained from patients with LOH. A total of 41 patients with LOH have been treated with TRT using 6 mg/day of GL for 3 months. Serum free testosterone levels (FT) and these four scores were compared before and after TRT.

Results. Serum FT levels and the scores for the four parameters of AMS, six of eight domains in SF-36, IIEF-5 and total IPSS improved significantly after 3 months TRT. In addition, all IPSS domains also improved significantly, and voiding disturbance seems to have improved more than storage disturbance (P?=?0.0280 vs. 0.0483).

Conclusion. TRT by administration of GL is considered to be effective in the improvement of not only ED and LOH symptoms, but also LUTS (especially voiding disturbance) of patients with LOH.     

Social interactions and the salience of social identity

We explore the effect of identity salience on behaviour in a simple social interaction. Specifically, we compare ultimatum bargaining across three treatments: priming subjects with a shared identity, priming subjects with an identity distinct from those with whom they will interact, and priming subjects with no particular identity. We find that subjects are most cooperative in the identity-priming treatment and least cooperative in the distinctiveness-priming treatment. Similarly, subjects reveal the highest demands in the identity-priming treatment and the lowest demands in the distinctiveness-priming treatment. We discuss the implications of these results with respect to the literature on organizational identity.     

Do people think about absolute or relative price differences when choosing between substitute goods?

The article presents experimental evidence that shows that people often consider relative price differences in addition to absolute differences when choosing between substitute goods. Because the choice between substitute goods is a very common one, this is an important finding. The experiment uses scenarios in various consumption categories: hotel rooms, flights, and books. Subjects were either students or participants in an economics conference. The data allow to reject the hypothesis that people think only about relative price differences in favor of the hypothesis that people think about both relative and absolute price differences. Whether the price given to the subjects is that of the high-quality good or of the low-quality good makes a large difference, a result that is related to the endowment effect and the status quo bias. Implications of the results for business strategy and other areas are also discussed.     

On robust forecasting in dynamic vector time series models

In this article, robust estimation and prediction in multivariate autoregressive models with exogenous variables (VARX) are considered. The conditional least squares (CLS) estimators are known to be non-robust when outliers occur. To obtain robust estimators, the method introduced in Duchesne [2005. Robust and powerful serial correlation tests with new robust estimates in ARX models. J. Time Ser. Anal. 26, 49–81] and Bou Hamad and Duchesne [2005. On robust diagnostics at individual lags using RA-ARX estimators. In: Duchesne, P., Rémillard, B. (Eds.), Statistical Modeling and Analysis for Complex Data Problems. Springer, New York] is generalized for VARX models. The asymptotic distribution of the new estimators is studied and from this is obtained in particular the asymptotic covariance matrix of the robust estimators. Classical conditional prediction intervals normally rely on estimators such as the usual non-robust CLS estimators. In the presence of outliers, such as additive outliers, these classical predictions can be severely biased. More generally, the occurrence of outliers may invalidate the usual conditional prediction intervals. Consequently, the new robust methodology is used to develop robust conditional prediction intervals which take into account parameter estimation uncertainty. In a simulation study, we investigate the finite sample properties of the robust prediction intervals under several scenarios for the occurrence of the outliers, and the new intervals are compared to non-robust intervals based on classical CLS estimators.     

On the distribution of quadratic functionals of the ordinary and fractional Brownian motions

In this paper we discuss some distributional properties of quadratic functionals of the ordinary and fractional Brownian motions (fBms). As far as the ordinary Brownian motion (Bm) is concerned, those properties have been established extensively. A transition from the Bm to the fBm is not straightforward. Some difficulties associated with dealing with the fBm are explained, and a way to solving the problem is indicated, and some conjectures are given.     

Canonical correlation analysis for the vector AR(1) model with ARCH innovations

This paper extends the results of canonical correlation analysis of Anderson [2002. Canonical correlation analysis and reduced-rank regression in autoregressive models. Ann. Statist. 30, 1134–1154] to a vector AR(1) process with a vector ARCH(1) innovations. We obtain the limiting distributions of the sample matrices, the canonical correlations and the canonical vectors of the process. The extension is important because many time series in economics and finance exhibit conditional heteroscedasticity. We also use simulation to demonstrate the effects of ARCH innovations on the canonical correlation analysis in finite sample. Both the limiting distributions and simulation results show that overlooking the ARCH effects in canonical correlation analysis can easily lead to erroneous inference.     

Empirical information criteria for time series forecasting model selection

In this article, we propose a new empirical information criterion (EIC) for model selection which penalizes the likelihood of the data by a non-linear function of the number of parameters in the model. It is designed to be used where there are a large number of time series to be forecast. However, a bootstrap version of the EIC can be used where there is a single time series to be forecast. The EIC provides a data-driven model selection tool that can be tuned to the particular forecasting task.

We compare the EIC with other model selection criteria including Akaike’s information criterion (AIC) and Schwarz’s Bayesian information criterion (BIC). The comparisons show that for the M3 forecasting competition data, the EIC outperforms both the AIC and BIC, particularly for longer forecast horizons. We also compare the criteria on simulated data and find that the EIC does better than existing criteria in that case also.     

Estimates of the quantiles of kendall's partial rank correlation coefficient

The sampling distribution of kendall's partial rank correlation coefficient, J_xy?z, is not known for N>4, where N is the number of subjectts. Moran (1951) used a direcr conbinatorial method to obtain the distribution of J_xy?z forN=4; however, ten minor computationa; errors in his Table 2apparently resulted in how erroneous entries for his frequency table. Since the parctial limits of the direct combinatorial approach have been reached once N>4, the first main objective of this paper was to obtain the exact distribution of J_xy?z for N=f, 6, and 7 using an electronic computer. The second was to use the Monte Carlo method to obtain reliable estimates of the quantiles of J_xy?z for N=8,9,...,30