Assume that you wish to estimate a population proportion, p. For the given margin of error and confidence level, determine the sample size required.
A researcher wishes to estimate the proportion of people within a certain population who are HIV positive. Obtain a sample size that will ensure a margin of error of at most 2.9 percentage points for a 90% confidence interval. Assume that it is reasonable to presume that the percentage of those sampled who are HIV positive will be between 3% and 7%.
A: 226
B: 805
C: 94
D: 210