CHALLENGE ACTIVITY 7.2.1: Confidence intervals for population proportions. Critical values for quick reference during this activity. Confidence level | Critical value 0.90 2* = 1.645 0.95 = 1.960 0.99 Z = 2.576 402294.2602416.qx3zqy7 Jump to level 1 A poll reported 41% support for a statewide election with a margin of error of 1.5 percentage points. How many voters should be sampled for a 99% confidence interval? Round up to the nearest whole number. Ex: 1234 # voters