Std Deviation Normal Distribution. Standard deviation and normal distribution standard deviation is a widely used measurement of variability or diversity used in statistics and probability theory. Standard deviation is a useful measure of spread for normal distributions.
When a distribution is normal then 68 of it lies within 1 standard deviation 95 lies within 2 standard deviations and 99 lies with 3 standard deviations. It shows you the percent of population. So the machine should average 1050g like this.
This fact is known as the 68 95 99 7 empirical rule or the 3 sigma rule.
Z scores tell you how many standard deviations from the mean each value lies. About 95 of the values lie within two standard deviations. Any normal distribution can be standardized by converting its values into z scores. The standard normal distribution also called the z distribution is a special normal distribution where the mean is 0 and the standard deviation is 1.
