A new cholesterol drug developed in Spencer's laboratories is being studied to determine its effectiveness. To do this, it was tested in a group of 16 adults (40 to 50 years old) and the results for the level of cholesterol in the blood before and one month after using the drug yielded means of 210 and 200 mg/dL respectively. Likewise, a standard deviation of 30 mg/dL was obtained for the difference in cholesterol levels. Considering that the differences between corresponding values are normally distributed, answer: Is the method of reducing blood cholesterol levels effective after one month of treatment? What statistic did you use to solve the problem? What is the value of the statistic?