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 99% confidence interval for the true mean age of oak trees.

The graph of the function f(x) = (x + 2)(x + 6) is shown below. which statement about the function is true? the function is positive for all real values of x where x > –4. the function is negative for all real values of x where –6 < x < –2. the function is positive for all real values of x where x < –6 or x > –3. the function is negative for all real values of x where x < –2.