Open Tertiary Education in Australia

The draft report of the Committee on Open University, Open Tertiary Education, is criticized on the grounds that it is overly conservative and makes little contribution to the opening up of tertiary education in Australia. The problems inherent in government committees, particularly in the field of education, are considered. Using the data provided in the report, the current closed system of tertiary education is criticized and a number of proposals, alternative to those made in the report, are presented for consideration.     

An International Pooled Analysis for Obtaining a Benchmark Dose for Environmental Lead Exposure in Children

Lead is a recognized neurotoxicant, but estimating effects at the lowest measurable levels is difficult. An international pooled analysis of data from seven cohort studies reported an inverse and supra‐linear relationship between blood lead concentrations and IQ scores in children. The lack of a clear threshold presents a challenge to the identification of an acceptable level of exposure. The benchmark dose (BMD) is defined as the dose that leads to a specific known loss. As an alternative to elusive thresholds, the BMD is being used increasingly by regulatory authorities. Using the pooled data, this article presents BMD results and applies different statistical techniques in the analysis of multistudy data. The calculations showed only a limited variation between studies in the steepness of the dose‐response functions. BMD results were quite robust to modeling assumptions with the best fitting models yielding lower confidence limits (BMDLs) of about 0.1–1.0 μ g/dL for the dose leading to a loss of one IQ point. We conclude that current allowable blood lead concentrations need to be lowered and further prevention efforts are needed to protect children from lead toxicity.     

String decomposition of full-period tausworthe sequences

Because of their nice properties relative to the frequency of occurrence of n-tuples, Tausworthe sequences have been used frequently in recent years as the basis for random number generators. This paper describes a similar result relative to the frequency of occurrence of maximal-length strings of like bits. In particular, for any full-period Tausworthe sequence, the distribution of string lengths is precisely equal to the expected distribution of string lengths for a truly random bit sequence of comparable size.     

The Set Point Theory of Well-Being Has Serious Flaws: On the Eve of a Scientific Revolution?

Set-point theory is the main research paradigm in the field of subjective well-being (SWB). It has been extended and refined for 30 years to take in new results. The central plank of the theory is that adult set-points do not change, except temporarily in the face of major life events. There was always some ‘discordant data’, including evidence that some events are so tragic (e.g. the death of one’s child) that people never regain their set-point. It was possible to dismiss these events as ‘exceptions’ and maintain the theory. However, several new findings are emerging, which cannot be dismissed as ‘exceptions’ and which appear to require substantial revisions or replacement of set-point theory. Many of these findings are based on the German Socio-Economic Panel Survey (SOEP 1984-), which provides the longest available time series on life satisfaction. Despite its centrality, the concept of the set-point is often not precisely defined. In this paper three alternative working definitions are offered. Depending on which definition is used, it is found that over 20 years 14–30% of German panel members recorded large and apparently permanent changes in their set-points. Changes of this magnitude are not compatible with set-point theory as currently understood. The challenge for SWB researchers now is to develop a theory which can account for change as well as stability.     

Imputation procedures for categorical data: their effects on the goodness-of-fit chi-square statistic

An imputation procedure is a procedure by which each missing value in a data set is replaced (imputed) by an observed value using a predetermined resampling procedure. The distribution of a statistic computed from a data set consisting of observed and imputed values, called a completed data set, is affecwd by the imputation procedure used. In a Monte Carlo experiment, three imputation procedures are compared with respect to the empirical behavior of the goodness-of- fit chi-square statistic computed from a completed data set. The results show that each imputation procedure affects the distribution of the goodness-of-fit chi-square statistic in 3. different manner. However, when the empirical behavior of the goodness-of-fit chi-square statistic is compared u, its appropriate asymptotic distribution, there are no substantial differences between these imputation procedures.     

The reality of net capital gains and annual profit on NZ primary producing businesses: data from a recent survey of all farm types

ABSTRACT

Annual net cash returns and net capital gains provide farmers with their actual and potential monetary rewards, respectively. This article reports on a national farm survey showing both actual and potential returns, on average, are not as high as might be imagined. This is supported by the findings of earlier studies and has implications for rural societies and their associated economies. Data on income, expenses and profit is presented as is data on farm value changes over the life of each farm. The information is adjusted for inflation to provide ‘real’ data. The profit and net capital gain figures are divided into groupings based on a range of criteria such as total farm capital, and labour compliment as a reflection of farm size. Statistically significant differences occur for some groupings such as farm type and farm size.     

A Theory for Coloring Bivariate Statistical Maps

Consideration of some practical uses of statistical bivariate maps—for example, display of association between variables—leads to principles for making effective use of color to represent data values. Effective color schemes for bivariate maps are viewed as continuous transformations from color models to the unit square with appropriate restrictions involving hue, saturation, and brightness. Several schemes, including those used by the U.S. Census Bureau, are criticized on the basis of this theory.