SAT Math Multiple Choice Question 861: Answer and Explanation
6. In a survey of 1,600 adults in the United States, 48% indicated that television istheir primary source of news. The margin of error for the survey is ±2.5%. Which valueis outside the interval that is likely to contain the exact percent of all adultsin the United States who get the news primarily from television?
- A. 45
- B. 47
- C. 49
- D. 50
Correct Answer: A
Category: Problem Solving and Data Analysis / Statistics and Probability
Strategic Advice: When the sample size of a random survey is sufficiently large, the margin of error provides a limit on how much the sample would differ from the responses of the population.
Getting to the Answer: To find the limit on how much the sample size would differ, add and subtract the margin of error:
48% - 2.5% = 45.5% and 48% + 2.5% = 50.5%
Based on this survey, the exact percent of all adults in the United States who get the news primarily from television should fall between 45.5% and 50.5%. The only answer choice that is outside this range is 45%, making (A) the correct answer.