Standard deviation

Statistics

The **variance** is the average difference of each value in the sample from the mean. As, by definition, the sum of the difference of each value from the mean would equal 0, the difference of each value from the mean is squared. (1st image below)

**It is very important to understand the difference between the standard deviation and the standard error,** see [SE vs. SD calculation]https://www.openanesthesia.org/se_vs-_sd_calculation/.

# 79%

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# 2012

Year asked