This site is intended for healthcare professionals
General Practice Notebook
Medical search

standard deviation (SD)

FREE subscriptions for doctors and students... click here
You have 3 open access pages.

The standard deviation gives the average distance of each of a set of observations from the mean.

It is represented by the Greek letter, sigma.

If the standard deviation is known then it can be stated that in a normally distributed population 68% of values will fall within one standard deviation of the mean, 95% within two and 99% within three standard deviations of the mean.

The standard deviation is the square root of the variance.

Links:

General Practice Notebook
General Practice Notebook
The information provided herein should not be used for diagnosis or treatment of any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions. Copyright 2016 Oxbridge Solutions LtdĀ®. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions LtdĀ® receives funding from advertising but maintains editorial independence. GPnotebook stores small data files on your computer called cookies so that we can recognise you and provide you with the best service. If you do not want to receive cookies please do not use GPnotebook.