In an experiment, evaluate the validity of the steps leading up to the conclusion for it to be valid. Random and systematic errors can contribute to the uncertainty of a measurement.

Introduction Wearable sensor systems may be useful for measuring head-impact exposure. Here, we tested the validity of in-ear sensors developed to improve head coupling. Methods First, the sensor was ...

The stratified random sample is always at least as accurate on the average as the random sample and its relative efficiency is a monotone increasing function of the size of the sample. No general ...