CHALLENGE ACTIVITY 4.3.1: Confidence intervals for population proportions Critical values for quick reference during this activity. Confidence level Critical value 0.90 2* = 1.645 0.95 2* = 1.960 0.99 2* = 2.576 403984.1980994.qx3zay7 v Jump to level 1 V A poll reported 66% support for a statewide election with a margin of error of 2 3.75 percentage points. 3 How many voters should be sampled for a 99%% confidence interval? Round up to the nearest whole number. Ex: 1234+ voters Check Next Feedback