Question

Suppose that in a random sample of 600 registered voters in one Florida county, 87.9% strongly agreed with the statement: "The State of Florida should have only one method of reading and counting ballots”. Based on this information, a statistician calculated, for the percentage of all registered voters with this view, a confidence interval extending from 85.8% to 90.0%. Find the confidence level associated with this i nterval.

Answer 1

tere, size of Sample sample is n= 600 proportion is & = 87.9% - 0.879 proportion is Confidence interval for true . (85.8%, 90%) • (0.858, 0.90) To find confidence level we have to find the 7 score associated with this interval. Formula for confidence interval for proportion , Von ( Ê & z. J A (1. Å I) § + 2!/BIG) - 0.90 10.899 (1–0:899) 50190-0879 z* = 1.5773 - V 600 => Now za - 1.5773 we have to find the a from 7 for which z score is 15773. table from z table, a = 5.75 % -). Q = 11:57 in confidence level is= 100 (1-0%) % • 100(1- 11:5) - 88.5 % . 100