# Drug Tests There is a 3.9% rate of positive drug test results among workers in the United States (based on data from Quest Diagnostics). Assuming that this statistic is based on a sample of size 2000, construct a 95% confidence interval estimate of the percentage of positive drug test results. Write a brief statement that interprets the confidence interval.

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Drug Tests There is a 3.9% rate of positive drug test results among workers in the United States (based on data from Quest Diagnostics). Assuming that this statistic is based on a sample of size 2000, construct a 95% confidence interval estimate of the percentage of positive drug test results. Write a brief statement that interprets the confidence interval.

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Step 1

The 95% confidence interval for the percentage of positive drug test result is obtained below:

The critical value is obtained below.

From the given information, the best estimates of the population proportion is 3.9% that is 0.039, the sample size is 2,000 and the confidence level is 0.95 and then from the standard normal table the critical value is 1.96.

The margin of error is obtained below:

Step 2

The 95% confidence interval for the proportion...

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