Characteristics of Normal Distribution

1)   Symmetrical about the mean (median and mode) 

a.     The mean divides the distribution in two where 50% of the distribution lies below the mean and 50% lies above the mean 

b.     The probability that a score falls below the mean is 50% 

c.     The probability that a score falls above the mean is 50% 

d.     Mean, median and mode are the same 


2)   Tails are asymptotic to the X axis 

a.     they run parallel to the X axis into infinity 

b.     The curves either side of the middle bell are asymptotic 


3)   Precise mathematical relationship between the curve, the mean and the standard deviation 

a.     the relationship between the mean and the standard deviation in a normal curve enables precise knowledge of the area, or percentage of scores, subsumed under any part of the curve