Are you getting more spam in your personal email account Sup

Are you getting more spam in your personal email account? Suppose that 45% of adult email users would say \"Yes.\" A polling firm contacts an SRS of 1800 people chosen from this population. If the sample were repeated many times, what would be the range of sample proportions who say \"Yes,\" according to the 99.7 part of the 68-95-99.7 rule? Range:

Solution

n=1800

p=0.45

99.7% falls within 3 standard deviation of mean.

standard deviation =sqrt(p*(1-p)/n)) =sqrt(0.45*0.55/1800)) =0.0117

lower limit =0.45-3*0.0117 =0.4149

upper limit =0.45+3*0.0117 =0.4851

Range = 0.4149 to 0.4851