The employees of cybertronics inc. need to complete a certification online. a random sample of 16 employees gives an average time for completion of all the coursework and passing the tests of 20 hours. the population standard deviation is unknown but the sample standard deviation is six hours. you can assume that the population of employees is fairly large. construct a 95% confidence interval for the average time required to complete the certification.

17.06 to 22.94

17.37 to 22.63

17.68 to 22.32

17.99 to 22.01

18.31 to 21.69

the employees of cybertronics inc. need to complete a certification online. a random sample of 49 employees gives an average time for completion of all the coursework and passing the tests of six hours. assume that the population standard deviation is six hours and the population of employees is fairly large. construct a 95% confidence interval for the average time required to complete the certification.

18.28 to 21.72

18.32 to 21.68

18.36 to 21.64

18.40 to 21.60

19.76 to 20.24