The package called 'Matlab' in Software Center is actually just an integration package (called matlab-support). As explained in the package description (
apt-cache show matlab-support):
This package does not provide MATLAB. Instead, it configures an existing MATLAB installation to integrate more comfortably in a Debian installation. . Currently it provides /usr/bin/matlab through the alternatives system, offers to work around incompatibilities between the libraries bundled with MATLAB and system libraries, and provides a helper utility meant to be used by other packages to compile MEX extensions. . Install this if you would like your MATLAB installation to behave more like an ordinary Debian package. Other packages may depend on this one if they install MATLAB code, for example in order to compile MEX extensions.
You will need to obtain your own licensed copy of Matlab for Linux first.
MATLAB is not free, and Linux distributions usually do not include limited demos, because of the amount of work it requires to bundle.
If you want to try something free and open, and MATLAB-like, try Octave or QtOctave (Octave + GUI). It uses the same dialect as MATLAB and the base math & graphs package are identical to MATLAB. It lacks in extensions however.
If you're in statistics, then another cool tool is IPython Notebook, found at http://ipython.org/ipython-doc/dev/notebook/. It's nice because you learn two in one. A good tool for math/stats and a respected and used programming language at the same time.