Answer:
A. The true proportion is within 3% of her estimate, with some degree of confidence.
Completed question:
A TV newscaster reports the results of a poll of voters, and then says, "The margin of error is plus or minus 3%." Explain carefully what that means.
A. The true proportion is within 3% of her estimate, with some degree of confidence.
B. The proportion of the population who voted for one candidate is 3% less than the percent of the population who voted for the other candidate.
C. The sample proportion is within 3% of her estimate, with some degree of confidence.
D. It means that 3% of the polls are invalid.
Explanation:
Margin of error can be defined as the maximum expected difference between the true value of a parameter and the estimated value.
In the case above, a tv newscaster reports the results of a poll of voters, and then says, "the margin of error is plus or minus 3%", according to the definition of margin of error, the maximum expected difference between the true proportion and the estimated proportion is 3%. Which means that the true proportion is within 3% of her estimate, with some degree of confidence