A medical researcher wants to test the effectiveness of the new cholesterol drug by comparing it to the existing most common drug. To test the claim, a sample of 31 patients with high cholesterol is chosen at random from a cardiologist's list of patients to take the new drug. Over the course of three months, this group lowers its total cholesterol by a mean of 39.4 points. The population standard deviation for this group is known to be 5.9 points. Another 36 patients with high cholesterol are chosen at random from a cardiologist's list of patients and are asked to continue taking the old drug. This group lowers its total cholesterol level by a mean of 39.2 points. The population standard deviation for this group is known to be 6.5 points. With 5% level of significance, test the claim that the mean decrease of cholesterol level from using the new drug is different from mean decrease of cholesterol level from using the old drug. Procedure: Select an answer Assumptions: (select everything that applies) Normal populations Population standard deviations are known Population standard deviation are unknown Independent samples Simple random samples The number of positive and negative responses are both greater than 10 for both samples