Forest management ~ Forest rangers wanted to better understand the rate of growth for younger trees in the park. They took measurements of a random sample of 50 young trees in 2009 and again measured those same trees in 2019. The data below summarize their measurements, where the heights are in feet.

Year	Mean	SD	n
2009	13	2.8	50
2019	24.7	9.4	50
Difference	11.7	6.83	50

Round all calculated values to 4 decimal places as appropriate.

1. Construct a 99 confidence interval for the mean difference between the height of trees in the park in 2009 and in 2019.

( , )

2. What conditions must be met if we want to perform a hypothesis test and answer the question of the management? Select all that apply:

A. Independently sampled pairs. B. There must be at least 3 levels of the categorical variable. C. Large samples and no extreme outliers. D. np^10andn(1p^)10np^10andn(1p^)10