GENERAL APPENDIXES
EXPERIMENTAL ERRORS AND ERROR ANALYSIS
•DEFINITIONS:
1.
Indeterminate error:
The random scatter in measured values obtained when we measure something
several times. No matter how careful we are or how good our equipment is, every measurement method has
some indeterminate error. Indeterminate error is also loosely known as the
experimental uncertainty
of a
measurement. Measured values are to be quoted as
. The Greek letter s is pronounced "sigma" and
it refers to the "standard deviation" of the measurement.
2. Mean:
Also called the
X
average value
. The average of
N
repeated measurements of the quantity x is often
abbreviated as
. It is calculated from the familiar formula:
x
±
!
x
x
=
i
=
1
N
!
This just means we add together all the measured values x
i
, and then divide by the number of
measurements.
3. Determinate error:
Also called
systematic error.
The difference between the average of our repeated
measurements of something, and its` "true" value. This represents a bias in the measurement method.
Nearly all measurement methods have some determinate error  the more
accurate
the method, the smaller
the determinate error.
4. Frequency distribution histogram:
Also called a
histogram.
A graph with the x axis divided into
bins (intervals) of values for the repeated measurements we make, and the y axis showing the number of
times the measured value fell in each bin. A bin labeled 5.05.2 by convention contains
That is, the value 5.2 exactly does not fall in the bin, but rather in the bin 5.05.2. Looking at a frequency
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '08
 RABE
 Physics, Normal Distribution, Standard Deviation, 01 seconds, 1 9m, 1.0meters, 1.9 meters

Click to edit the document details