Question 1116768
z=1.645 
p=63/280=0.225 
CI=p-z(&#8730;(p(1-p) )/n))&#8804;&#928;<p+z(&#8730;(p(1-p) )/n)) 
CI=0.225-1645(&#8730;(0.225(1-0.225) )/280))&#8804;&#928;<0.225+1.645(&#8730;(0.225(1-0.225)/280))
CI=0.184<&#928;<0.266