Explanation:
Normal distribution was given by Pierre Simon. Karl Guss is generally given the credits ti finding out the normal distribution error. Manufacture process and natural processes both create this type of distribution. This distribution also called Gaussian distribution a uni-modal bell curve. it is spread symmetrically in the center of the curve. It occurs when the occurrence can occur equally above and below the curve. Six sigma is devoted to the memory which is used analyzing the normal data or assuming the normality of curve. Many natural occurrences and processes with common cause variation exhibit a normal distribution.