Question 1186282
81/1200=0.0675, p hat
z=(p hat-p(/sqrt(p*(1-p)/n)
=-0.0025/0.0072
=-0.35 (-0.3472)


Check with normal approximation 
the sample proportion is 81/1200=0.0675
the sd is sqrt (np(1-p))=sqrt 81*0.9325= sqrt (75.53)=8.69
z=(x bar-mean)/sd
=(81-84)/8.69, where the 84 is 7% of the 1200 expected
=-3/8.69
=-0.35 (-0.3452)