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HyperNiche for Windows 98, 00, ME, NT,
XP, Vista, and 7
Multivariate Analysis of Ecological Data
Version 2
To order: In Canada or USA call 1-800-690-4499 or Order
Online or Fax/Mail |
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Comparison of NPMR in
HyperNiche with other methods of habitat modeling
Comparison of GAM or GAMs (Generalized additive models) and NPMR:
- GAMs and NPMR share the use of smoothing functions. Individual terms are combined
additively in GAMs and multiplicatively in NPMR.
- GAMs model interactions by adding specific terms, while they are modeled automatically
with a multiplicative kernel function in NPMR.
- Commercial software for GAMs is more expensive and harder to use than NPMR in
HyperNiche.
- GAMs have no theoretical basis for additive terms in controlling species response
functions, while NPMR has an explicit theoretical and biological foundation as a
statistical representation of Shelford’s Law of Tolerance.
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Comparison of logistic regression and NPMR:
- In logistic regression (a form of generalized linear model, GLM) the analyst must
specify in advance the form of the response function for each predictor and their
interactions (e.g. sigmoid, hump-shaped, linear), even when the analyst has no theoretical
basis for choosing one response type over another, while NPMR is open to any form of
response function.
- Interactions must be modeled explicitly with logistic regression, by adding specific
terms, while they are modeled automatically in NPMR.
- Commercial software for logistic regression is more expensive and harder to use than
NPMR in HyperNiche.
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Comparison of MARS (Multivariate adaptive regression splines) and NPMR:
- MARS fits separate splines to different intervals of the predictors, while NPMR applies
a multidimensional kernel smoother.
- Both MARS and NPMR can fit response surfaces that differ fundamentally in shape in
different parts of the surface.
- Both MARS and NPMR seek the best model by a numerically intensive and exhaustive search
through the domain of possible models.
- Both MARS and NPMR are well suited to modeling interactions. NPMR does so automatically,
while MARS users request consideration of interactions up to a specified level.
- Commercial software for GAMs is more expensive and harder to use than NPMR in
HyperNiche.
- MARS has no theoretical basis in the biology of species response to habitat factors,
while NPMR has an explicit theoretical and biological foundation as a statistical
representation of Shelford’s Law of Tolerance.
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