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Random and Systematic Errors

```
Date: 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.
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

- Doctor Shawn, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
High School Statistics

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