HALLENGE 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 2* = 1.960 0.99 2.576 Jump to level 1 A poll for a statewide election has a margin of error of 1.3 percentage points How many voters should be sampled for a 95% confidence interval? Round up to the nearest whole number. Ex: 1234 = | voters