I know I have been late in posting this graph and I could have done it a lot earlier. It was just that I quit my job for 6 months, went to Delhi for mains Preparations, dropped Physics for Public Administration, took coaching for PubAd at Mohanty, delivered in Mains and came back to job. I don't know whether it is the boredom at job or the missing joy of studying sociology and stimulation of grey cells or simply tiredness with life, perhaps all of them that took to me greater levels of depression.
The calculation also shows that there is positive correlation of 0.64 between average marks in a subject and the number of students opting for it , thus reinforcing my argument.
Anyways heres the chart I was talking about in my last post.
It just displays an approximate increasing trend in average marks in a optional with increase in number of students opting for that optional. It simply means if you have equal capability in all subjects then your chances are better if you opt for a subject that is taken up by more students.
It becomes more clear with the following scatter chart.
My advice to any newbie to UPSC is to go for "popular subject" as far as popular.
Those with engineering backgrounds insisting on a science subject can try Chemistry but better would be PubAd, Psychology, Philosophy, etc.