Bias in not only present in machine systems, but also in natural geological systems. The United States Geological Survey (USGS) realized bias is present in calculating the flow of rivers in Oregon. Obtaining the correct flow is important, since the placement of a hydroelectric dam may depend on the flow. To compensate for bias in the measurements, the USGS used a complex series of equations, and determined the correct flow accordingly.
Correcting the bias in an Ohmmeter is a very simple process. An ohmmeter is a test instrument that measures resistance. It has a moving needle on a background scale, and the needle moves according to how much resistance is placed across the test leads. Ohmmeters drift out of accuracy due to a number of factors, including the internal battery losing power. The error produced is called bias. To correct the bias, an electrician touches the two probes together. While they are together, a small adjustment knob is turned, until the needle lines up to zero on the scale.
Scientists rely extensively on hypothesis and probabilities when first designing an experiment. A hypothesis is a premise outlined before the experiment is conducted, stating that a certain outcome may take place. Research will prove or disprove the original hypothesis. A great deal of bias exists in probabilities, since the probability of an outcome may, in fact, be contrary to the original hypothesis. Researchers at Cornell University studied bias in hypothesis by using a branch of mathematics called differential geometry. They developed a complex series of equations resulting in a better method for correcting bias in hypothesis.
Correcting the bias in electronic systems is called calibration. The machine must be calibrated accurately before use, since the bias will produce inaccurate readings. Correcting the bias in an ohmmeter is simple. For large, complex machines, such as X-ray machines or an MRI (Magnetic Resonance Imaging) machine, extensive expertise is required to calibrate the system. For this reason, organizations such as the American Society for Quality offer certification programs for technicians so they can prove competence when correcting the bias on a complex system.