CHALLENGE ACTIVITY 5.3.1: 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 380310.1974868.qx3zcy7 Jump to level 1 A poll reported 43% support for a statewide election with a margin of error of 3.1 percentage points. How many voters should be sampled for a 90% confidence interval? Round up to the nearest whole number. Ex: 1234 voters 2 3 Check Next