Magnetotelluric Sampling and Geoelectric Hazard Estimation: Are National‐Scale Surveys Sufficient?

Bounded influence magnetotelluric response function estimation

S U M M A R Y Robust magnetotelluric response function estimators are now in standard use in electromagnetic induction research. Properly devised and applied, these have the ability to reduce the influence of unusual data (outliers) in the response (electric field) variables, but are often not sensitive to exceptional predictor (magnetic field) data, which are termed leverage points. A bounded ...

Machine Estimation of Timber Volumes for Use in Sampling Surveys

Sampling for Web Surveys

Web surveys are frequently based on samples drawn from panels with large amounts of nonresponse or haphazard selection. The availability of large-scale consumer and voter databases provides large amounts of auxilliary information for both panelists and population members. Sample matching, where a conventional random sample is selected from a population frame and the closest matching respondent ...

A Comparison of Techniques for Magnetotelluric Response Function Estimation

Spectral analysis of the time-varying horizontal magnetic and electric field components yields the magnetotelluric (MT) impedance tensor. This frequency dependent 2x2 complex tensor can be examined for details which axe diagnostic of the electrical conductivity distribution in the Eaxth within the relevant (frequency dependent) inductive scale length of the surface observation point. As such, p...

Adaptive sampling in behavioral surveys.

Studies of populations such as drug users encounter difficulties because the members of the populations are rare, hidden, or hard to reach. Conventionally designed large-scale surveys detect relatively few members of the populations so that estimates of population characteristics have high uncertainty. Ethnographic studies, on the other hand, reach suitable numbers of individuals only through t...