CHALLENGE ACTIVITY 4.3.1: 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 2* = 2.576 403984.1980994.qx3zay7 v Jump to level 1 1 In a poll of 1000 randomly selected voters in a local election, 403 voters were 2 against fire department bond measures. 3 What is the sample proportion p? EX: 0.123 4 What is the margin of error m for the 95% confidence level? Ex: 0.123