This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
The standard normal distribution- 
Select and explain. 
A. It skewed to the left, B. Has mean - 1.0, C. Has standard detion = 0.0, D. Has mean = 0
D: Has mean = 0
Answer: D: Has mean = 0 
Explanation: Ref:Parks 23rd edition pg 849 Stadardised normal curve : Smooth, bell-shaped, perfectly symmetrical curve based on an infinitely large number of observations . Total area of the curve= 1 Mean= 0 Standard detion = 1 Mean, median and mode all coincide.