Monday, April 1, 2013

AVEDEV Function

The AVEDEV function Returns the average of the absolute deviations of data points from their mean. The AVEDEV function can be down into five parts:

Data Set
90
91
84
93
97

Mean (average of data set)
Sum of data set

90+91+84+93+97
=    91
Number of data points

5

 Deviation of Data Points (difference between mean and data point)
Data
90
91
84
93
97
Mean
91
91
91
91
91
Deviation
-1
0
-7
2
6

Absolute Deviation of Data Points (absolute value of the deviation of data point)
Data
90
91
84
93
97
Mean
91
91
91
91
91
Deviation
-1
0
-7
2
6
Absolute Deviation
1
0
7
2
6

*Note the absolute value of a number is just the positive version of that number. In simple terms just remove any negative sign if there is one.

AVEDEV (absolute deviations of data points from mean)
Sum of Absolute Deviations

1+0+7+2+6
~    3.667
Number of Data Points

6

So what does this show? Well if you had five students with grades of 90, 91, 84, 93 and 97 on a test, you could use the AVEDEV function to determine how far each individual student is from the class average. You can also use this to identify if one piece of data is so far off the rest of the data.  Statisticians use this function to determine how accurate a set of data is when testing various data for experimentation's.

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