After exploring different threads I realized that Statistics can be very high as well as very low scoring subject and the key is to have aptitude for this subject and good practice.
as with aptitude I think I have it being much interested in Maths and logic(No as such background in Stats though) . I read that there there are approx. 12 chapters to be prepared from two different books. My question is that normally how much time would be required to prepare as it seemed like relatively small syllabus (12 chapters) .I am thinking 2 weeks would be enough with 8 hours a day . Please inform about your perception or experience ...

Thanks in advance