15. A national corporation analyzed its overhead costs by state. It noticed that its Oklahoma offices had a mean monthly overhead cost of $37115 with a standard deviation of $2920. Its Texas office had a mean monthly overhead cost of $120850 with a standard deviation of $19400. In the month of June of 2013 both offices kept costs below their mean. The Oklahoma office had an overhead cost $35, 100 and the Texas office had an overhead cost of $115,300. Use Z-Scores to determine which office did the best job reducing overhead costs. 16. The Oklahoma office of a national corporation has a mean overhead cost of $37115 with a standard deviation of $2920. In August of 2013 the Oklahoma office had overhead costs with a Z-Score of +1.5. Find the overhead cost for the Oklahoma office for the month of August 2013. 17. A student scored 97 on an Elementary Statistics test that had a mean score of 85 with a standard deviation of 12. The same student also scored 130 on a History test that had a mean score of 108 with a standard deviation of 21. Use Z-Scores to determine on which test the student did the best