Compute the standard deviation of the data sample.
−1,3,5,9,12
Round your answer to two decimal places.

Question

Compute the standard deviation of the data sample.
−1,3,5,9,12
Round your answer to two decimal places.

anonymous · Answer

please help @Hero @jim_thompson5910 @RadEn @SithsAndGiggles @whpalmer4

jim_thompson5910 · Answer

Here is a good page that explains how to find the standard deviation http://www.mathsisfun.com/data/standard-deviation-calculator.html you can even type in your data values and it will show you the step by step calculation (based on your values) to get the to the answer

jim_thompson5910 · Answer

be careful to choose the right standard deviation (either sample or population)

jim_thompson5910 · Answer

Since this is a data sample (which represents a larger population), we go with sample standard deviation

anonymous · Answer

thats where I got confused! so with a larger population you do n-1 in the denominator right?

jim_thompson5910 · Answer

well if your entire population is just those set of values, then you go with population standard deviation

jim_thompson5910 · Answer

However, it states this is a data sample. So this is a sample drawn from a larger population

So we use a sample standard deviation

jim_thompson5910 · Answer

that means you divide by N-1 instead of just N

jim_thompson5910 · Answer

so you are correct

jim_thompson5910 · Answer

usually, you will do stats on a sample that represents a much larger population

so you'll usually use the sample standard deviation (instead of the population version)

anonymous · Answer

okay thats where i couldn't find the right answer, now i got it! and how can you tell the difference between the two? is it just wording like "data sample"?

jim_thompson5910 · Answer

yeah specifically "sample"

whpalmer4 · Answer

this business of having the two different meanings (and so many not mentioning which one they mean) annoys me to no end :-)

jim_thompson5910 · Answer

and most of the time, you'll deal with samples in stats

you will hardly know much about the population (since it's just too big)

jim_thompson5910 · Answer

stats exists to estimate stuff about the population based on samples drawn

jim_thompson5910 · Answer

so population standard deviations seem silly to me really

whpalmer4 · Answer

this is about the best description I've encountered of which one to use!

jim_thompson5910 · Answer

unless all you care about are those numbers, then you'd use the population version

whpalmer4 · Answer

I'd give two medals, if I could!

anonymous · Answer

ahhh this makes so much more sense now! thank you so much Jim!

jim_thompson5910 · Answer

np