Note: I accidentally posted this in the precalculus sub-forum. Please accept my apologies for cross posting. If a mod could remove the other thread I would be grateful. Once again, sorry for poor etiquette...

Hello all,

I would like to ask what is probably a simple question for you all... *blush*

I am having some trouble understanding the notation of an equation used to calculate the timing of the seasonal peak of plankton.

Here it is: (I am afraid I am unfamiliar with TeX, so I will simply paste an image of the equation...)

(Central Tendency, T)

Where x_{m}is the mean abundance in month M (January=1, Feb=2,...,Dec=12)

I understand that the denominator is simply SUM from 1 to 12 the mean abundance i.e. X1 + X2... +X12. I don't understand the M.xm part, though; does the full stop/period/dot represent a multiplication...?

Apologies if this is all elementary...

Many thanks in advance for any help offered