Data on 4100 college graduates show that the mean time required to graduate with a​ bachelor's degree is 5.39 years with a standard deviation of 1.59 years. Use a single value to estimate the mean...

Data on 4100 college graduates show that the mean time required to graduate with a​ bachelor's degree is 5.39 years with a standard deviation of 1.59 years. Use a single value to estimate the mean time required to graduate for all college graduates.​ Also, find the​ 95% confidence interval for the mean time required to graduate for all college graduates.

The estimate for the mean time required to graduate for all college graduates is how many years?