This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Pearson's measure of skewness - 
Select and explain. 
A. Mode - Mean/SD, B. Mean - Mode/SD, C. SD/Mode - mean, D. Mean - Mode/SD
B: Mean - Mode/SD
Answer: B: Mean - Mode/SD 
Explanation: Step 1: Subtract the median from the mean: 70.5 – 80 = -9.5.
Step 2: Divide by the standard deviation: -28.5 / 19.33 = -1.47. Caution: Pearson's first coefficient of skewness uses the mode. 
Therefore, if the mode is made up of too few pieces of data it won't be a stable measure of central tendency.