Issac, BYU-Idaho student, found an old article in the school paper, the Scroll, that asserted that 11% of girls "wait for their missionary". Now that some years have passed and the missionary age limits have changed, and Isaac wants to revisit the question and would like to estimate what proportion of girls "wait for their missionary". If he is willing to accept a margin of error of 3%, and a 90% confidence level, how many observations does he need in his sample?