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 = 1.960 0.99 2* = 2.576 377568.2850564.peng/7 Jump to level 1 A poll reported 68% support for a statewide election with a margin of error of 4.22 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