I am planning to apply for Masters in Computer Science in US for FALL 2015.

Majority of my work in college and office has been in developing desktop, mobile and web applications (except my final year project which was on Human Computer Interaction). I'm finding it difficult to relate my entire work to a particular speicialization in the universities. By specialization I mean tracks like Data Sciences(Machine Learning), Cloud Computing, Human Computer Interaction. Some people told me that application development comes under Human Computer Interaction, some others told me it's not exactly human computer interaction to be developing mobile or web apps, it is if you are designing the apps or devices that host these apps.

Honestly, I am not sure completely about which specialization I want to do, but I feel I have a vibe for Machine learning and data sciences. I just have one mini-project in that area from undergrad. I wanted to do more with Machine Learning in my undergrad, but all the teachers who were experts in that field were occupied, so I had to settle for my next most interested topic Human Computer Interaction.

I got to know that when Profs are reviewing SOPs of students, they feel confident to choose a person who knows what he wants clearly and has done something substantial in that field prior to applying. Hence some of my seniors suggested me to apply for what I have the most experience in, so that I have better chances of getting selected. In most universities, we are allowed to explore tracks once we start attending school for about 2 weeks and then decide our specialization. It's not really mandated by what I have written in SOP.

I would be very glad if anyone can guide me in the right direction by answering the following questions.

Here are my questions
1. Is it okay if I am generic in my SOP that I want to do Masters in Computer Science without mentioning a specialization? Would this hurt my chances?
2. Does application development come under Human Computer Interaction? If I write about that in my SOP would it increase my chances?

Thanks in Advance.