Weights of Zero
Theoretically, zero sampling weights should not be possible. Sampling weights are supposed to be the inverse of the probability of being sampled, so if this is the case, they cannot be zero. But often weights are adjusted through various procedures and they can be set to zero, or even a negative value. (Aside: only svyset with iweights will handle negative weights, all other commands will exit with an error mentioning negative weights.) Zero weights can also be created when one is modeling a subpopulation. For instance, suppose you have males and females in your sample and you want to model only the males.
Hence, when there are only a few zero weights, the difference in standard errors will be very, very small—as it is in this example. Only when there are substantial numbers of zero weights will the standard errors differ appreciably. skinPercent is undoable, queryable, and editable.This command edits and queries the weight values on members of a skinCluster node. If no object components are explicitly mentioned in the command line, the current selection list is used. Note that setting multiple weights in a single invocation of this command is far more efficient than calling it once per weighted vertex.Most connectionist models have assumed that each connection has a single weightwhich is adjusted during the course of learning. Despite the emergingbiological evidence that changes in synaptic efficacy at a single synapse occurat many different time-scales (Kupferman, 1979; Hartzell, 1981), there havebeen relatively few attempts to investigate the computational advantages ofgiving each connection several different weights that change at differentspeeds.