CHALLENGE ACTIVITY 5.8.1: Confidence intervals for population proportions. Critical values for quick reference during this activity. Confidence level Critical value 0.90 z* = 1.645 0.95 z* = 1.960 0.99 2* - 2.576 V Jump to level 1 V A poll reported 52% support for a statewide election with a margin of error of 3.25 percentage points. How many voters should be sampled for a 90%% confidence interval? Round up to the nearest whole number. Ex. 1234 voters