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Paper: |
Looking for a Slope Change in a Linear Relationship |
Volume: |
512, Astronomical Data Analysis Software and Systems XXV |
Page: |
229 |
Authors: |
Cardiel, N.; Marino, R.A.; Pascual, S.; Ceballos, M.T.; Gil de Paz, A.; Sánchez, S.F. |
Abstract: |
The initial understanding of many scientific problems relies on the simplifying
assumption that some data of interest can initially be modelled by a linear
relationship. In some cases, the simultaneous fit of two lines, joined at an
intermediate point, constitutes the next natural step towards a more elaborate
modelling. In this sense, the method of Lagrange multipliers can be used to
obtain such a fit with the location of the intermediate point left as a free
parameter. This work shows the results of simple simulations in which the
simultaneous fit to two joined lines is compared to the simultaneous fit of two
independent lines (i.e., two lines that do not necessarily coincide at the
intermediate point), and also to the traditional single ordinary least squares
fit. These simulations reveal some biases that should be taken into account
when using that kind of fitting procedure. |
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