Suppose that the true but unknown proportion of defective blu-ray players is 0.04. if many samples of size 200 are taken, the expected mean of the sample proportions will be

the given sample size proportion or p = 0.04 or 4%

standard deviation, sigma Ф = √p(1-p)/n = √0.04(1-0.04)/200 = 0.0318

However the question is asking for the expected mean, which is the sample size of n = 200 times the size proportion, p = 0.04, giving 200 x 0.04 = 8