Thread: Standard Deviation and Varians

I first of all apologize if this is the wrong category. This is for a Statics class at college level, but basic statistics.

I am really having a hard time and confusing myself when it comes to the standard deviation and variations. The formulas (do the best I can without the keys needed on the keyboard) are:

O2m = O2 squared / N - this is variance

Om = this is standard deviation (standard deviation / N squared = standard deviation)

When given a problem are we be given one or the other to calcuate and then continue with the rest of the steps. For example if I am given the standard deviation of 8 and my N = 10 then 8/10 = .80 so this would be my standard deviation.

Would I also then calcuate a variance or or is that only if you are given the variance in the problem you would then use the formula to determine your variance.

This is the only part I am having a really hard time grasping. Ugh.

Thanks for your help!!

Hello Nurse Toby.

The problem seems to be the terminology
Let be the variance of one observation whether thats or ....
It's the variance of each one of them.

NOW the sample mean is

and the variance of is

and the st deviation of is

Originally Posted by nursetobe

This is for a Statics class at college level

Statics??? I thought you wanted to be a nurse, not an engineer.

Originally Posted by matheagle

Hello Nurse Toby.

hahahaha

Thanks for your help matheagle

Anonymously, trust me if it were up to me I wouldn't be taking statistics but it is required for a BSN!!

Great site by the way!!!

You're welcome, my friends call me the beagle, short for mathbeagle my alter ego
I solve math problems during the day and fight crime at night
no wait, it's the other way around