The average lifetime of an oak tree is found to be 55 years from a sample of 10 oak trees. Previous records indicate that the standard deviation is 15 years when the results follow a Gaussian distribution. Construct a 95% confidence interval for the true mean age of oak trees. What distribution is used in constructing confidence intervals in this problem? [ Select ] What is Maximal Margin of Error (E) at 95% confidence? [ Select ] Construct a 95% confidence interval [ Select ] V