I have a rule to implement which says that if standard deviation of a set of measurements is > x, then y is true.
Problem is that my values could be anything like:
1,1.1,1.2,1.2,1.3..
or
100, 100.4, 100.5 , 101.2....
Is standard deviation dependent of values i.e. does the larger size of the second row has an impact on standard deviaton ?
The Standard Deviation is a measure of how spread out the numbers in your data are. So if your numbers have the same difference, even with higher values then you will got the same standard daviation. A small example to clarify, using matlab:
If your data is : $ 1 ,2,3,4,5,6,7,8,9$ then std is $2.7386$.
If your data is : $ 10 ,20,30,40,50,60,70,80,90$ then std is $27.386$.
However if your data is $ 101 ,102,103,104,105,106,107,108,109$ then std is also $2.7386$.
So as you see, the idea is not the values in the data, the idea is how your data are spread. The first and the third data are compltely different, however have the same std, this is because they are equally spread, unlike the second data.
Hope this makes the idea clear.