posted by chalulu .
A researcher at a major hospital wishes to estimate the proportion of the adult population of the U.S. that has high blood pressure. How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the tgrue proportion by more than 4%?
n = [(z-value^2 * p * q)]/E^2
...where n = sample size, z-value will be 2.58 using a z-table to represent the 99% confidence interval, p and q represent proportions, E = .04, ^2 means squared, and * means to multiply.
Note: p and q will both be .5 if no value is stated.
Plug the values into the formula and finish the calculation. Round your answer to the next highest whole number.