<p>Ok i have the barrons book, and from what I understood to get variance you square the standard deviation, but on the ti-83 you could do variance and i got a different answer, i then realized that i was geting the answer of not the standard. dev. sqaued but the thing above it if you go to stat and calc, and then do the statistics for l1 or any other list its sx sqared not the o with a slash on top squared. but in the barrons book they do standard deviation sqared.
Which is it?
so to find standard deviation by hand is it still the mean minus you number for all those numbers and square each one of them? if you did it by hand?
So what do you use for variance the stand. deviation (ox and square it) or the SX squared which you could just use throw 2nd math number 8 or throw the catalog under v??? which is the right way??? </p>
<p>Also the barrons book has interquartile range throw removing something, and im just confused because before i used q3-q1 but it says thats also right, what it gives different answers. Someone tell me what is going on, especially the standard deviation part</p>
<p>P.S. sx part uses n-1 for denominator if you did it by hand (i still dont know what it is, since the calculator uses this number squared)</p>
<p>Any helpful answer is greatly aprreciated!!!</p>