If you’re in an advanced chemistry or college chemistry course you’re probably going to be asked to calculate the standard deviation of your results for a lab. It’s called a lot of things, but most usually either standard deviation or relative standard deviation. Here’s how to calculate it:
SD or RSD = the square root of ((sum of (mean or average – value) / number of values – 1)
Then some professors or TAs will ask for the percent standard deviation or the percent relative standard deviation. The way to calculate the percent standard deviation is:
Standard Deviation Value / mean or average value x 100
Hope this helps clear things up.
[Image Credit] Chad Miller