The circumference of a particular species of tree was thought to be different depending on certain geographical factors. An SRS of 60 trees is selected in Sequoyah National Forest, where it is found that = 6 meters with a standard deviation = 3 meters. A second SRS of size 40 is independently selected in Yellowstone National Forest, and it is found that = 4 meters with a standard deviation = 2 meters. Let 1 and 2 represent, respectively, the true mean circumferences of this particular species of tree. Assume the two-sample t procedures are safe to use.
1. A 95% confidence interval for 1 – 2 is
2.The researcher tests the following hypotheses: H0 : 1 = 2, Ha : 1 ≠ 2
The numerical value of the two-sample t statistic is
3.The researcher tests the following hypotheses: H0 : 1 = 2, Ha : 1 ≠ 2. The p-vale for the test is
4. The degrees of freedom for these t procedures are closest to
5. The researcher tests the following hypotheses: H0 : 1 = 2, Ha : 1 ≠ 2
The 90% confidence interval is 2 ± 0.83 meters. Based on this confidence interval,