what is the probability of getting 16 out of 20 questions correct on a true/false test?
20C16*0.5^20
nCr(20,16)*(1/2)^20 = 0.0046205520629883 = 0.46%
That is assuming that you totally guess every single answer.
20! / [16! x 4! x 2^20] = 0.00462 x 100 =o.462%
