SOLUTION: In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive. (a) C

Question 182969: In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be
engaged in safety and security-related jobs, and found that 1,143 were positive. (a) Construct a
95 percent confidence interval for the population proportion of positive drug tests. (b) Why is the
normality assumption not a problem, despite the very small value of p?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive.
(a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.
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p-hat = 1143/86991 = 0.013
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E = 1.96*sqrt[0.013*0.087/86991] = 2.89x10^-7
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95% CI: 0.013-2.89x10^-7 < p < 0.013+2.89x10^7
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(b) Why is the normality assumption not a problem, despite the very small value of p?
I'll leave that to you.
Cheers,
Stan H.

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