Splitting of signal into different components for calculation of PSD In BCI competition 3 dataset 5, It has been stated that we have to take 8-30 Hz frequency and break it with resolution of 2 Hz then it will result in 12 components but I am finding out only 11 components.Why??
The description can be found out here...

http://www.bbci.de/competition/iii/desc_V.html
Hint:

$$f_i=8+i\cdot 2\;\text{Hz},\quad i=0,1,\ldots,11$$

Note that $f_0=8\,\text{Hz}$ and $f_{11}=30\,\text{Hz}$. So you have 12 frequencies in the range $[8,30]\,\text{Hz}$, including both edge frequencies.