1. The Normal Curve Packet #23

2. Normal Curve  Referred to as a bell- shaped curve  Perfect mesokurtic distribution

3. Characteristics of a Perfect Normal Curve  The mean, median and mode will be the same and will divide the curve exactly in half  68% of the scores fall within one standard deviation of the mean  95% of the scores fall within two standard deviations from the mean  99% of the scores fall within three standard deviations from the mean  The two tails of the curve get closer and closer to zero without reaching zero

4. Normal Distributions  Many human variables fall on a normal or close to normal curve  IQ  Height  Lifespan  Shoe size  Because of this, one can estimate how many people will have a specific IQ, etc, just by knowing two things  The mean and the standard deviation

5. Look at IQ  Average IQ is 100  Standard deviation is 15  Knowing those facts, one can say that  50% of people will have an IQ of 100 or higher  68% will have an IQ between 85 and 115  95% will have an IQ between 70 and 130  2.5% will have an IQ of 130 or above  84% will have an IQ of 85 or above