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This paper provides a systematic review of the weak-form market efficiency literature that examines return predictability from past price changes, with an exclusive focus on the stock markets. Our survey shows that the bulk of the empirical studies examine whether the stock market under study is or is not weak-form efficient in the absolute sense, assuming that the level of market efficiency remains unchanged throughout the estimation period. However, the possibility of time-varying weak-form market efficiency has received increasing attention in recent years. We categorize these emerging studies based on the research framework adopted, namely non-overlapping sub-period analysis, time-varying parameter model and rolling estimation window. An encouraging development is that the documented empirical evidence of evolving stock return predictability can be rationalized within the framework of the adaptive markets hypothesis.

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This paper mvestigates three techniques for the estimation of conditional llmedependent betas: (a) a multivariate generalised ARCH approach; (b) a tlmevarymg beta market model approach suggested by Schwert and Seguin (1990); and (c) the Kalman filter technique. These approaches are applied to a sample of returns on Australian industry portfolIOs over the perIOd 1974-1996. The evidence found in this paper, based on in-sample forecast errors, overwhelmingly supports the Kalman filter approach When out-of-sample forecasts are considered the evidence again finds in favour of the Kalman filter approach.

The present survey investigated the communication activities of a general adult population. Particular attention was given to speaking and listening activities. The study includes a broad spectrum of occupations.Questionnaires containing a communication log were mailed to four hundred randomly selected adults in the San Diego area. (One hundred and seventy-three logs were returned.) The logs, divided into fifteen minute segments, contained the following categories: sleep, no communication, conversation, television, reading, listening, speaking. Brief definitions for each of these categories were contained in a cover letter.Results, in general, indicated: 1 ) that administrators, salesmen, students, teachers and professionals rank as high communicators; 2 ) approximately three-fourths (72.8%) of our waking time is given over to communication activities.

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