Challenge activities 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 2* = 1.960 0.99 2* = 2.576 377108.2356942.qx3zqy7 Jump to level 1 1 In a poll of 1000 randomly selected voters in a local election, 906 voters were 2 against school bond measures. 3 What is the sample proportion p? Ex: 0.123 4 What is the margin of error m for the 90% confidence level? Ex: 0.123 1 Check Next Feedback