In an election poll, 200 people were surveyed and 45% expressed their likelihood to vote for a particular candidate. the margin of error on this estimated support is closest to
A margin of error is an amount (usually small) that is allowed for in case of miscalculation or change of
circumstances. A general approach for finding a margin of error involves using the standard deviation of a sample
proportion.
Roughly 95% of all normally distributed data fall
within two standard deviations of the mean. So the margin of error is two times the standard deviation (SD) margin of error = 2*SD SD=sqrt(p*(1-p)/n) p is probability of the event and n is the sample size. In our case, p=0.45 and n=200. SD=sqrt(0.45*0.55/200)=sqrt(0.001)-0.03
