The perfectly smooth and symmetrical curve, resulting from the expansion of the binomial (q+ p) n when n approaches infinitely is known as the normal curve. Thus, the normal curve may be considered as the limit toward which the binomial distribution approaches as n increases to infinity. Alternatively we can say that the normal curve represents a continues and infinite binomial distribution when neither p nor q is very small. Even though p and q are not equal, for very large n we get perfectly smooth and symmetrical curve. Such curves are also called Normal Probability curve or Normal curve of Error or Normal Frequency curve. It was extensively developed and utilized by German Mathematician and Artsonomer Karl Gauss. This is why it called Gaussian curve in his honor. The normal distribution was first discovered by the English Mathematician Dr. A. De Moivre. Later on French Mathematician Pierre S. Laplace developed this principle. This principle was also used and developed by Quetlet, Galton and Fisher.
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