What Is A Normal Distribution?
A Basic Introduction
The Normal Distribution, like any Distribution is the probability function that shows how the variables of a population (or sample) are distributed. The distribution of variables is important as it allows us to better understand and make inferences about the data. The unique thing about the Normal Distribution is that is symmetrical to the mean. This mean that once one identifies the mean (the mathematical average) the distribution is even on both sides of the mean — meaning, the probability of a observing a variable decreases evenly as the variable being considered is further away from the mean.
As one can see, the image on the left shows an example of a Normal Distribution. Lets consider that 50 (the mean) is the average liters of water a person uses when they shower. If the probability distribution of the data we collect appears to be a Normal Distribution, then that would mean that the probability of finding an individual who uses less than 35 (15 units below the mean) liters of water is as rare, on average, as finding an individual who uses more than 65 liters (15 units above the mean).