CHALLENGE ACTIVITY 5.8.1: Confidence intervals for population proportions. Critical values for quick reference during this activity. Confidence level Critical value 0.90 2* = 1.645 0.95 z* = 1.960 0.99 z* = 2.576 361666.1905872.qx3zay7 V Jump to level 1 1 V A poll reported 52% support for a statewide election with a margin of error of 2 4.56 percentage points. 3 How many voters should be sampled for a 99% confidence interval? Round up to the nearest whole number. 4 Ex: 1234 + voters 3