For a Given Level of Precision and Confidence Level, a Researcher

Multiple Choice

For a given level of precision and confidence level, a researcher determines that he needs a sample size of 400. The study was to find out that the proportion of people who smoke is 30 percent. For the same level of precision and confidence, she would have needed the same sample size if the proportion of those who smoked were to change to:

A) 40 percent.
B) 50 percent.
C) 60 percent.
D) 70 percent.
E) As long as the precision and confidence stay the same, the proportion doesn't affect the required sample size.