Find the mirgin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.
90% confidence ; n=480 , x=120
E = z·σ/√n
At 90% confidence, z = 1.645
E = 1.645·σ/√480
To complete this, you need the value of σ -- do you have this value? If so, you can finish this calculation.
