caused by uncontrollable fluctuations in variables that
affect experimental results. For example, air fluctuations occurring as students open and close
lab doors cause changes in pressure readings. A sufficient number of measurements result in
evenly distributed data scattered around an average value or mean. This positive and negative
Reading: Analysis of Errors Revised 2/9/13
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scattering of data is characteristic of random errors. The estimated standard deviation (the
error range for a data set) is often reported with measurements because random errors are
difficult to eliminate. Also, a "best-fit line" is drawn through graphed data in order to "smooth
out" random error