Showing papers by "Ronald A. Thisted published in 1988"

Elements of Statistical Computing: NUMERICAL COMPUTATION

Abstract: Statistics and computing share many close relationships. Computing now permeates every aspect of statistics, from pure description to the development of statistical theory. At the same time, the computational methods used in statistical work span much of computer science. Elements of Statistical Computing covers the broad usage of computing in statistics. It provides a comprehensive account of the most important computational statistics. Included are discussions of numerical analysis, numerical integration, and smoothing. The author give special attention to floating point standards and numerical analysis; iterative methods for both linear and nonlinear equation, such as Gauss-Seidel method and successive over-relaxation; and computational methods for missing data, such as the EM algorithm. Also covered are new areas of interest, such as the Kalman filter, projection-pursuit methods, density estimation, and other computer-intensive techniques.

Cervical injury in head trauma

Abstract: Criteria for excluding cervical spine injury in patients who have sustained blunt head or neck trauma were prospectively studied at four hospitals in the Chicago area. The authors attempted to define a subset of these adult patients who, based on clinical criteria, could reliably be excluded from cervical spine radiography, thus avoiding unnecessary radiation and saving considerable time and money in their evaluation. Patients fell into four groups: (1) patients who were awake, alert, and had no complaint of neck pain or tenderness on physical examination: (2) patients who were awake, alert, but had complaint of neck pain or tenderness on physical examination laterally over the trapezius muscle only: (3) patients who were awake, alert, but had complaint of central neck pain or tenderness on physical examination over the cervical spine or center of the neck; and (4) patients who were not fully awake or alert, were clinically intoxicated, had other painful or distracting injuries, or had focal neurologic findings. Patients in group 4 had significantly more fractures (21/387) when compared with all other patients (7/478). Patients with central neck pain or tenderness (group 3) had significantly more fractures ( 7 237 ) than patients without pain or tenderness or with these findings limited to the trapezius area (0/236). It is clear that patients who have altered mental status, abnormal examination findings, distracting injury, or pain or tenderness over the cervical spine must have cervical spine radiographs. In a patient who is awake, alert, has normal physical examination findings, is undistracted by other painful injuries, and has no pain or tenderness in the neck or these findings are limited to the trapezius area, there is less than 1% chance of a cervical spine fracture, with a 90% confidence limit. Our data strongly suggest we can modify our use of cervical spine radiographs in patients sustaining blunt head trauma without subjecting patients to undue risk.