Hi, I'm working on some chemistry and i'd like for the unit to me mol/l not mol/m^3. How do i fix this? I googled it and it seems like the unit is the universal standard for concentration but i wasn't taught this in school as we were told to use mol/l. 

I've tried googling and following the guides on the site but i honestly cant figure out what im doing wrong.

Picture for reference 

I'm doing a statistic analysis on a lot of data which i have imported from Excel into a matrix. I've got about 2880 data points and i'm trying to use regression and its giving me an error which i do not know how to deal with.

How would i execute the following calculate? I know i could use the statistics package but i want to do with with the formula. I'm trying to find the standard deviation. Look at the attached picture so see. I've also attached a copy of the calculations in maple format.

Download Test.mw

Also another little side thing, but not necessary. Is it possible to have a matrix with empty spaces in it and return it?