5,478 research outputs found
Why bayesian âevidence for H1â in one condition and bayesian âevidence for H0â in another condition does not mean good-enough bayesian evidence for a difference between the conditions
Psychologists are often interested in whether an independent variable has a different effect in condition A than in condition B. To test such a question, one needs to directly compare the effect of that variable in the two conditions (i.e., test the interaction). Yet many researchers tend to stop when they find a significant test in one condition and a nonsignificant test in the other condition, deeming this as sufficient evidence for a difference between the two conditions. In this Tutorial, we aim to raise awareness of this inferential mistake when Bayes factors are used with conventional cutoffs to draw conclusions. For instance, some researchers might falsely conclude that there must be good-enough evidence for the interaction if they find good-enough Bayesian evidence for the alternative hypothesis, H1, in condition A and good-enough Bayesian evidence for the null hypothesis, H0, in condition B. The case study we introduce highlights that ignoring the test of the interaction can lead to unjustified conclusions and demonstrates that the principle that any assertion about the existence of an interaction necessitates the direct comparison of the conditions is as true for Bayesian as it is for frequentist statistics. We provide an R script of the analyses of the case study and a Shiny app that can be used with a 2 Ă 2 design to develop intuitions on this issue, and we introduce a rule of thumb with which one can estimate the sample size one might need to have a well-powered design
Adaptive Investment Strategies For Periodic Environments
In this paper, we present an adaptive investment strategy for environments
with periodic returns on investment. In our approach, we consider an investment
model where the agent decides at every time step the proportion of wealth to
invest in a risky asset, keeping the rest of the budget in a risk-free asset.
Every investment is evaluated in the market via a stylized return on investment
function (RoI), which is modeled by a stochastic process with unknown
periodicities and levels of noise. For comparison reasons, we present two
reference strategies which represent the case of agents with zero-knowledge and
complete-knowledge of the dynamics of the returns. We consider also an
investment strategy based on technical analysis to forecast the next return by
fitting a trend line to previous received returns. To account for the
performance of the different strategies, we perform some computer experiments
to calculate the average budget that can be obtained with them over a certain
number of time steps. To assure for fair comparisons, we first tune the
parameters of each strategy. Afterwards, we compare the performance of these
strategies for RoIs with different periodicities and levels of noise.Comment: Paper submitted to Advances in Complex Systems (November, 2007) 22
pages, 9 figure
Axiomatic Characterization of the Mean Function on Trees
A mean of a sequence Ď = (x1, x2, . . . , xk) of elements of a finite metric space (X, d) is an element x for which is minimum. The function Mean whose domain is the set of all finite sequences on X and is defined by Mean(Ď) = { x | x is a mean of Ď } is called the mean function on X. In this paper the mean function on finite trees is characterized axiomatically
Computability of simple games: A complete investigation of the sixty-four possibilities
Classify simple games into sixteen "types" in terms of the four conventional
axioms: monotonicity, properness, strongness, and nonweakness. Further classify
them into sixty-four classes in terms of finiteness (existence of a finite
carrier) and algorithmic computability. For each such class, we either show
that it is empty or give an example of a game belonging to it. We observe that
if a type contains an infinite game, then it contains both computable ones and
noncomputable ones. This strongly suggests that computability is logically, as
well as conceptually, unrelated to the conventional axioms.Comment: 25 page
The Effect of Bankruptcy Laws on the Valuation of Risky Consumer Debt
In a market setting with perfect information, a consumer recognizes that he can influence the state-contingent returns, and hence the pric, of his risky debt by the decision variables that determine the collateral and promised payments. This paper examines the effect of bankruptcy laws on the feasible consumption opportunities of borrowers and lenders in order to determine the necessary requirements for the bilateral debt market to be perfectly competitive.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72017/1/j.1540-6288.1989.tb00348.x.pd
Sen and the art of educational maintenance: evidencing a capability, as opposed to an effectiveness, approach to schooling
There are few more widely applied terms in common parlance than âcapabilityâ. It is used (inaccurately) to represent everything from the aspiration to provide opportunity to notions of innate academic ability, with everything in between claiming apostolic succession to Amartya Sen, who (with apologies to Aristotle) first developed the concept. This paper attempts to warrant an adaptation of Senâs capability theory to schooling and schooling policy, and to proof his concepts in the new setting using research involving 100 pupils from 5 English secondary schools and a schedule of questions derived from the capability literature. The findings suggest that a capability approach can provide an alternative to the dominant Benthamite school effectiveness paradigm, and can offer a sound theoretical framework for understanding better the assumed relationship between schooling and well-being
Sustainability and the Measurement of Wealth
We develop a consistent and comprehensive theoretical framework for assessing whether economic growth is compatible with sustaining well-being over time. The framework focuses on whether a comprehensive measure of wealth â one that accounts for natural capital and human capital as well as reproducible capital â is maintained through time. Our framework also integrates population growth, technological change, and changes in health. We apply the framework to five countries that differ significantly in stages of development and resource bases: the United States, China, Brazil, India, and Venezuela. With the exception of Venezuela, significant increases in human capital enable comprehensive wealth to be maintained (and sustainability to be achieved) despite significant reductions in the natural resource base. We find that the value of âhealth capitalâ is very large relative to other forms of capital. As a result, its growth rate critically influences the growth rate of per-capita comprehensive wealth.
The Limits to Sustainability Science: Ecological Constraints or Endless Innovation?
Ecological principles must govern sustainability, yet sustainability science is largely concerned with social-environmental interactions and barely considers physical limits on resource use. Whether it is possible to overcome such limits can be contested, but the issues raised by a macroecological perspective should be a fundamental part of the United Nations Conference on Sustainable Development (Rio+20)
Profiling a decade of information systems frontiersâ research
This article analyses the first ten years of research published in the Information Systems Frontiers (ISF) from 1999 to 2008. The analysis of the published material includes examining variables such as most productive authors, citation analysis, universities associated with the most publications, geographic diversity, authorsâ backgrounds and research methods. The keyword analysis suggests that ISF research has evolved from establishing concepts and domain of information systems (IS), technology and management to contemporary issues such as outsourcing, web services and security. The analysis presented in this paper has identified intellectually significant studies that have contributed to the development and accumulation of intellectual wealth of ISF. The analysis has also identified authors published in other journals whose work largely shaped and guided the researchers published in ISF. This research has implications for researchers, journal editors, and research institutions
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