Are Hadoop and Python SciPy used for the same?
I think you're quite confused.  

Hadoop is a collection of software that contains a a distributed file system called HDFS. Essentially HDFS is a way to store data cross a cluster.  You can access file stores as you would in a local file store (with some modification) and modify things via Java API.  Furthermore, ON TOP OF the file system there exist a MapReduce engine that allows for distributive workflow. 

Python on the other hand is a generic programming language that can be made to do a myriad of task such as build a web applciation, to generating reports and even peforming analytics.  

SciPy is a package that can be used in conjunction with Python (and often numpy) as a way to perform common scientific task.

Truthfully, they focus on different paradigms.  If you have LARGE DATA (ie terabytes worth of it), it might be worth wild to setup a hadoop cluster (ie multiple servers and racks) and use Java MapReduce, Hive, Pig or Spark (of which there is a python version) to do analytics.  

If your data is small or you only have one computer, then it probably makes sense to just use python instead of adding the overhead of setting up hadoop.

Edit:  Made correction via comment.