Errors when installing rtcheck

Question

I'm trying to install "rtcheck". I do sudo apt-get install rtcheck, but during the installation an error occurs.

  andrea@andrea-K53SD:/$ sudo apt-get install rtcheck
     [sudo] password for andrea: 

Reading package lists... Done 

 Building dependency tree       

Reading state information... Done

E: Unable to locate package rtcheck
     andrea@andrea-K53SD:/$

What does this mean?