2,441,224 research outputs found
New probabilistic interest measures for association rules
Mining association rules is an important technique for discovering meaningful
patterns in transaction databases. Many different measures of interestingness
have been proposed for association rules. However, these measures fail to take
the probabilistic properties of the mined data into account. In this paper, we
start with presenting a simple probabilistic framework for transaction data
which can be used to simulate transaction data when no associations are
present. We use such data and a real-world database from a grocery outlet to
explore the behavior of confidence and lift, two popular interest measures used
for rule mining. The results show that confidence is systematically influenced
by the frequency of the items in the left hand side of rules and that lift
performs poorly to filter random noise in transaction data. Based on the
probabilistic framework we develop two new interest measures, hyper-lift and
hyper-confidence, which can be used to filter or order mined association rules.
The new measures show significantly better performance than lift for
applications where spurious rules are problematic
Qualitative Evaluation of Associations by the Transitivity of the Association Signs
We say that the signs of association measures among three variables {X, Y, Z}
are transitive if a positive association measure between the variable X and the
intermediate variable Y and further a positive association measure between Y
and the endpoint variable Z imply a positive association measure between X and
Z. We introduce four association measures with different stringencies, and
discuss conditions for the transitivity of the signs of these association
measures. When the variables follow exponential family distributions, the
conditions become simpler and more interpretable. Applying our results to two
data sets from an observational study and a randomized experiment, we
demonstrate that the results can help us to draw conclusions about the signs of
the association measures between X and Z based only on two separate studies
about {X, Y} and {Y, Z}.Comment: Statistica Sinica 201
The association between accounting and market-based risk measures
The paper derives operating and financial measures of leverage and tests their association with market based measures of equity risk. It is the first such study to use purely accounting-based data to derive the leverage measures. In line with previous literature it conducts a new test on the relative importance of operating and financial leverage. The results suggest that operating costs have a greater impact
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