since n=10 is small you must use the binomial distribution and not approximate this via a normal

=.85" alt="H_0=.85" /> vs <.85" alt="H_a<.85" />

I doubt we will get exactly .05

where X is a binomial rv with n=10 and p=.85

DARN close............. .049969798878515

at http://stattrek.com/Tables/Binomial.aspx

and u still have an inferior duck