% Enter t=dataC and y=dataABS as columnwise vectors
And then you enter them as rows :)
Stick a transpose ( ' ) on those three lines and it works.
ETA: Well, "works" is a subjective term... I suspect the line a = X\dataC; is supposed to be a = X\dataABS;
ETA(2): In response to question below, here's the code using function handles. At the end of this, ymodel is a function of t that you can evaluate ad naseum.
% Enter t=dataC and y=dataABS as columnwise vectors
dataABS=[1.003 1.038 1.079 0.466 0.402 0.469 0.156 0.237 0.188]';
dataT=[9.94 9.17 8.34 34.23 39.62 33.93 69.86 58.00 64.85]';
dataC=[10 11 10 6 7 6 2 3 2]';
% Form the design matrix
dmat = @(t) [ones(size(t)) exp(-t) t.*exp(-t)];
% Calculate model coefficients
a = dmat(dataC)\dataABS;
T = (0:0.5:10)';
ymodel = @(t) dmat(t)*a;
plot(T,ymodel(T),'-',dataC,dataABS,'o'), grid on
