Respuesta :

The margin of error (MOE) can be calculated by using the formula:

MOE = 1.96 sqrt [p (1 – p) / n]

 

So substituting the values:

MOE = 1.96 sqrt [0.5 (1 – 0.5) / 400]

MOE = 0.049

 

Therefore answer:

A. 0.049