The standard deviation for a population is=14.7

. A sample of19

observations selected from this population gave a mean equal to142.80

. The population is known to have a normal distribution.

Round your answers to two decimal places.

a.Make a99% confidence interval for

.

(

Enter your answer;99% confidence interval, lower bound

,

Enter your answer;99% confidence interval, upper bound

)

b.Construct a97%

confidence interval for

.

(

Enter your answer;97% confidence interval, lower bound

,

Enter your answer;97% confidence interval, upper bound

c.Determine a95%

confidence interval for

.