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 V Jump to level 1 1 V A poll reported 49% support for a statewide election with a margin of error of 2 1.77 percentage points. 3 How many voters should be sampled for a 90% confidence interval? Round up to the nearest whole number. A Ex: 1234 voters 2 3 Check Next Feedback