isi 2013-was negative marking there?

[abc]

guys was there any negative marking in today's paper?? it wasnt written on the paper. i attempted all, but later many peope told me there was negative marking. what do u guys think? how was the paper overall??

[kam]

yes there was, if you check the information booklet they put on their website it is written there

[ss]

@kam can you please tell exactly where this is mentioned ?

thanks

[ss]

oh found it ..thankx..!

[abc]

hey, can u post that link

[monti]

it was announced in my centre that there is no negative marking in the paper.....so relax

[IISSII]

Exactly...some teacher came to my center too and announced that there is no negative marking this time! So, even I marked everything n did not leave any question unmarked!

[pbansal]

they give 4 marks for correct,o for incorrect(therefore technically no negative marking) but 1 mark for unattempted,

[Amit Goyal]

Any marking scheme can be thought of as a function from all possible outcome to scores:

m:{Attempted & Correct, Attempted & Wrong, Not Attempted} ---> R

For example, In ISI the marking scheme was:
m(Attempted & Correct) = 4
m(Attempted & Wrong) = 0
m(Not Attempted) = 1

Note that the above marking scheme is fair:
Expected Score from randomly selecting an answer = (1/4)(4) + (3/4)(0) =  1 =  Score from not attempting it

Consider now an alternative marking scheme
n:{Attempted & Correct, Attempted & Wrong, Not Attempted} ---> R
defined as follows
n(Attempted & Correct) = 3
n(Attempted & Wrong) = -1
n(Not Attempted) = 0

Note that n = m - 1 and is therefore the monotonic transformation of the marking scheme m. Also, it preserves the property that
Expected Score from randomly selecting an answer = (1/4)(3) + (3/4)(-1) =  0 =  Score from not attempting it

Therefore, n and m are equivalent. We have just shifted the origin.

Conclusion: If marking scheme n has "negative marking" then m also has negative marking. In fact, for all decision making purposes the two schemes should be treated as equivalent.