A stable test for checking if a matrix is a nonsingular M -matrix is presented. Its computational cost is, in the worst case, O(n2) elementary operations higher than the computational cost of Gaussian elimination. The test can be applied to check if a nonnegative matrix has spectral radius less than 1.

BACKGROUND Hospitals are the most costly and important components of any health care system, so it is important to know their economic values, pay attention to their efficiency and consider factors affecting them. OBJECTIVE The aim of this study was to assess the technical scale and economic efficiency of hospitals in the West Azerbaijan province of Iran, for which Data Envelopment Analysis (...

Ninety-two patients were tested in this way. In 69 cases the average I.Q. arrived at from the two Performance Tests was higher than the Stanford I.Q. In three the results were the same, and in 20 the Stanford I.Q. was higher than the Average Performance I.Q. Further, where the Performance I.Q. was above the Stanford, it was much more above it than the Stanford was above the Performance Test res...