Random and Systematic ErrorsDate: 03/05/2002 at 14:32:54 From: Richard Subject: Random/Systematic Errors Hello, While reading a book I came across the terms 'random errors' and 'systematic errors'. I don't understand the meanings of these two phrases. Thank you. Date: 03/05/2002 at 16:44:41 From: Doctor Shawn Subject: Re: Random/Systematic Errors Thanks for writing to Dr. Math, Richard. Systematic errors are easier to deal with. Imagine that you are taking weight measurements on a scale. The only problem is that the scale is broken, and adds a half pound to everything you measure with it. Obviously, this will skew your data. Fortunately for you, though, it affects every measurement in the exact same way (which is why it's called "systematic"). If you weigh a sample that you know for a fact is exactly one pound, then you can correct for the error. Random errors are harder to spot and harder to correct for. Going back to the scale example, it would be as if the scale arbitrarily weighed everything placed on it anywhere from a half pound light to a half pound heavy. It could even give you the exact right measurement. Using the standard weight won't help you this time, though, because every time you measure the standard, the scale will read something different. Random errors are unavoidable, simply because there aren't any perfect instruments, and because people make mistakes. They should usually follow a bell curve distribution, though, so you can use statistical analyses like standard deviation to try to correct for them. You can also try to avoid them as much as possible by using good measuring equipment. I hope that helps. Write back if you have other questions, or if you want to talk about this some more. - Doctor Shawn, The Math Forum http://mathforum.org/dr.math/ |
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