We randomly select 110 fish from a reservoir and measure the length of them. The average length of the fish is 31 cm with a standard deviation of 2.79 cm. (a) Find a 90% confidence interval for the...

We randomly select 110 fish from a reservoir and measure the length of them. The average length of the fish is 31 cm with a standard deviation of 2.79 cm.

(a) Find a 90% confidence interval for the average length of all fish in the reservoir  .
        ≤ U ≤

(b) Find a 95% confidence interval for the average length of all fish in the reservoir  .
         ≤ U ≤

(c) Find a 99% confidence interval for the average length of all fish in the reservoir  .

        ≤ U ≤