CHALLENGE ACTIVITY 7.2.1: Confidence intervals for population proportions. Critical values for quick reference during this activity. Confidence level | Critical value 0.90 z* = 1.645 0.95 z* = 1.960 0.99 z* = 2.576 V Jump to level 1 V A poll reported 65% support for a statewide election with a margin of error of 2 4.29 percentage points. 3 How many voters should be sampled for a 90% confidence interval? Round up to the nearest whole number. Ex: 1234 voters 2 3 Check Try again Feedback