It's believed that as many as 21% of adults over 50 never graduate from high school we wish to see if this percentage is the same among the 25 to 30 age group. a. How many of this younger age group must be surveyed in order to estimate the proportions of non grades to within 10% in 90% confidence?
b. Suppose we want to cut the margin of error to 3% what is the necessary sample size?
c. What symbolizes would produce a margin of error of 2%?