Most common answers on the SAT

fignewton
Mon, 14 Mar 2011 16:32:06 +0000

A little while ago, I did a study of this question using 13 past (QAS) exams (math only).

The results are consistent with a uniform random distribution of answers, i.e., p(A) = p(B) = p(C) = p(D) = p(E) = 0.2.

For a total of 572 multiple choice questions, here were the letter frequency numbers and corresponding z-scores:

A 108 -0.67
B 116 0.17
C 119 0.48
D 120 0.59
E 109 -0.56

(expected value for each: 114 to 115).

You would need a z-score of more than 1.96 or less than -1.96 to say with a decent level of confidence that these letter frequencies are NOT uniformly random.