Homework Soursewhat is the minimum sample size of adults that must be surve
what is the minimum sample size of adults that must be surveyed in order to be 90% confident that the sample percentage is in error by no more than five percentage points assuming that 72% of the respondents believe that the economy is improving
what is the minimum sample size of adults that must be surveyed in order to be 90% confident that the sample percentage is in error by no more than five percentage points assuming that 72% of the respondents believe that the economy is improving
what is the minimum sample size of adults that must be surveyed in order to be 90% confident that the sample percentage is in error by no more than five percentage points assuming that 72% of the respondents believe that the economy is improving
Solution
Note that
n = z(alpha/2)^2 p (1 - p) / E^2
where
alpha/2 = 0.05
Using a table/technology,
z(alpha/2) = 1.644853627
Also,
E = 0.05
p = 0.72
Thus,
n = 218.1750241
Rounding up,
n = 219 [ANSWER]
