I have been following LPTHW ex. 46 in which it says to put a script in bin directory that you can run. I don't get the idea of using script when you have modules. What extra significance do  scripts provide? Are scripts executable *.exe files(in case of windows) rather than modules which are compiled by python? If modules provide all the code needed for the project then do scripts provide the code needed to execute them? How are scripts and modules linked to each other, if they do so?
Scripts can be used as stand-alone programs for tasks both simple and complex. 
When you put them in a bin directory, and have the bin directory in your PATH, you can execute them just like an exe, assuming you have configured the interpreter correctly (in Windows), or have put #!/usr/bin/python as the top line for Linux.
For example, you might write a Python script that computes the mean of a list of numbers passed into stdin, stick it in your bin directory, and execute it just like you would a C program for the same purpose.
What do scripts(stored in bin directory of the project) do in addition to modules in a python project?