User-suplied inputs:
Column B         Concentrations of the standards (X)
Column C	Instrument readings  of the standards (Y)
Column J	Instrument Readings of the unknowns

Calculated outputs:
Cell B28	n=number of x,y data points
Cell B27	sumx=?x
Cell C27	sumy=?y
Cell D27	sumxy=?x*y
Cell E27	sumx2=?x*x
Cell B29	meanx=sumx/n
Cell C27	meany=sumy/n
Cell B31	slope=(n*sumxy - sumx*sumy) / (n*sumx2 - sumx*sumx)
Cell B32	intercept=meany-(slope*meanx)
Cell F27	ssy=?(Y-meany)^2
Cell G27	ssr=?(Y-intercept-slope*X)^2
Cell C37	R2 =1-(ssr/ssy)
Column K	Calculated concentrations of the unknowns	(InstrumentReading-intercept)/slope