The state agriculture department tested 203 fuel samples across the state in 2009 for accuracy of the reported octane level. For premium grade, 14 out of 105 samples failed. How many samples would be needed to create a 99 percent confidence interval that is within .02 of the true proportion of premium-grade fuel-quality failures?

Question

Quizplus · Accepted Answer

= 14 / 105 = .133 n = p(1 − p)(z/E)² = .133(.867)(2.576/.02)² = (.1153)(128.8)² = 1912.76 = 1913

The State Agriculture Department Tested 203 Fuel Samples Across the State