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The circumference of a particular species of tree was thought to be different depending on certain geographical factors. A random sample of 60 trees is selected in Sequoia National Forest, where it is found that sample mean = 6 meters with a standard deviation = 3 meters. A second random sample of size 40 is independently selected in Yellowstone National Forest, and it is found that sample mean = 4 meters with a standard deviation = 2 meters. Let [.11 and [.12 represent, respectively, the true mean circumferences of trees from Sequoia National Forest and Yellowstone National Forest respectively. Assume the two- sample t procedures are safe to use. The researcher tests the following hypotheses: Ho'\"1=\"2'Ha'\"1 \"'2 Find the value of the test statistic