WTF is sample deviation

[Siva]

My biochem lab needs me to cacluate sample deviation, what is it? I googled and all I got were results for standard deviation or stuff that I just don't understand. It says both that I have to calculate both standard and sample deviation, so its not just another term for standard deviation.

You'd think if stat wasn't a prereq they'd provide some formulas for the students or at least a text that has that kind of info.

 

[Stiganator]

Sample deviation is an approximation of the standard deviation if I recall correctly. Sometimes you may not have the appropriate data, so you guestimate with the sample deviation. This is often an exercise to show how the approximate deviation differs from the actual standard deviation.

 

[pol II]

Stiganator is right; the sample deviation is an estimate of thr "real" or "true" standard deviation and is usually represented by an italicized, lower-case "s." The true SD is represented by sigma.

 

[MobiusPizza]

Standard deviation has two kinds:
Parent population standard deviation and Sample standard deviation

Parent population as the name suggest is the population where your sample is taken from. Then the above is self-explanatory

If what you measured, which is your case, is a sample based on a parent population, your Biochem lab just wanted you to calculate the standard deviation of your sample. Simple as that

========
Extending what Stiganator has said:
Usually in statistics you NEVER gonna know what the population standard deviation is. Such as what is the standard deviation of height of all people living in Florida. But you can take a sample and estimate the parent standard deviation from the sample deviation by making what in statistical term an unbiased estimator so we can get a rough idea of what the true parent standard deviation is by guressing from sample.