Question 471546
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Hi,
Note: The probability of x successes in n trials is: 
P = nCx* {{{p^x*q^(n-x)}}} where p and q are the probabilities of success and failure respectively. 
nCx = {{{n!/(x!(n-x)!)}}}
Above appropriate for use with a binomial model:

In this case p & q cannot be determined because some of the students surveyed
had no opinion and could not be counted in the numbers determining  p or q
and therefore this is not a binomial model