All the necessary values have been found to calculate the margin of error. We have za/2 = 1.960, p* = 0.26, and E = 0.05. Substitute these value, rounding the result to four decimal places. (a/2)p*(1 - p) n E2 (1.96)2(0.26)(1 -0.26) Since this value represents a sample size, a whole number should be used. Using the whole number smaller than this value will result in a larger than desired margin of error, so the value should be rounded up to the nearest whole number. Thus, a sample size of should be used to ensure the margin of error of 0.05 is obtained.