Janet wants to estimate the percentage of people who have been required to take a drug test for work. She surveys 250 individuals and finds that 175 have taken a drug test for work. Identify the values needed to calculate a confidence interval at the 98% confidence level. Then find the confidence interval.

98% of  confidence interval for the true population

(0.6326 , 0.7674)

Step-by-step explanation:

Step(i):-

Given sample size 'n' = 250

She surveys 250 individuals and finds that 175 have taken a drug test for work.

sample proportion

level of significance ∝ = 0.05

98% of  confidence interval for the true population is determined by

Z₀.₀₂ = 2.326

Step(ii):-

98% of  confidence interval for true population is determined by

( 0.7 -  0.0674 , 0.7 + 0.0674)

(0.6326 , 0.7674)

Conclusion:-

98% of  confidence interval for the true population is determined by

(0.6326 , 0.7674)