Chances of getting an offer to study economics at Cambridge

Hey guys,I applied to Cambridge for economics, and I was just wondering if I actually have real shot. I have 8 A*s in my IGCSEs and and my AS UMS scores are as follows:
MATHEMATICS:
C34: 195/200 (I took C34 first and I'll take C12 along with my A2 units)
M1: 100/100
S1: 96/100

PHYSICS:
Unit 1: 120/120
Unit 2: 120/120
Unit 3: 52/60

CHEMISTRY:
Total for Units 1,2,3: 300/300

ECONOMICS:
Unit 1: 87/90
Unit 2: 93/100

In my personal statement I wrote about why I want to study economics (the clichèd 'betterment of society' and how much it interests me and all that. But I'm afraid I didn't display any significant engagements with the subject beyond my academic curriculum, and the ECAA admission test I took went really bad. Do you think the good UMS scores will make up for the lack of extracurriculars engagements in the subject?

No one can say - not even an Admissions Tutor without reviewing your entire application (including your likely and upcoming interview) against the gathered field.

The ECAA is just one aspect and a "weakness" there can certainly be made up with "strengths" elsewhere. Oh, and you don't need extracurriculars.

Anyway, all you can do is await the interview and then decision day, along with everyone else.