Central Tendency and Dispersion Background: Researchers conducted a study to evaluate the effects of a new drug on the systolic blood pressure (SBP) of patients with hypertension. They selected 20 patients and recorded their SBP before and after the administration of the drug. Data (in mm Hg): Before Drug Treatment: 140, 155, 149, 160, 145, 134, 150, 158, 146, 152, 147, 153, 141, 139, 154, 159, 148, 143, 136, 151 After Drug Treatment: 133, 148, 141, 152, 137, 127, 144, 150, 140, 146, 138, 147, 134, 132, 149, 151, 139, 136, 129, 143

Questions: 1. Calculate the mean and median of the SBP for patients before and after the drug treatment.

2. Calculate the range and the interquartile range (IQR) for the SBP before and after the drug treatment.

3. Based on the measures of central tendency, what can you infer about the effect of the drug on the SBP of the patients ?

4. Based on the measures of dispersion, do the SBP measurements appear to be more variable before or after the drug treatment? Why ?