A knowledge of basic statistics is important for the researcher.
Describe your data:
Total Number or "N", Mean, Median, Mode and Standard Deviation are used to describe your data.
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The Total Number or "N" is the number of observations made.
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Mean: This is the average of the data. Adding the values of all of the observations and dividing the total by the total number of observations or "N".
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Median: This is the middle value of the observations.
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Mode: This is the most frequent observation.
Thus for the data sequence of 2, 5, 7, 9, 10, 12, 12, 18, 20
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The "N" is 9
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The Mean is 10.33
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The Median is 10
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The Mode is 12
The Standard Deviation is a description of how tightly the observed data points are clustered around the mean. One standard deviation should include approximately 68% of the data points. Two Standard Deviations should include approximately 95% of the data points and three Standard Deviations should include approximately 99% of the data points.
For the above example one Standard Deviation is 5.85.
Microsoft Excel and Sun Microsystems's Open Office can calculate Standard Deviation and Means. Download Open Office