Normal Distribution
.jpg "illustration of symmetric and skewed")
If a random variable has a probability distribution whose graph is continuous, bell-shaped, and symmetric, it is called a Normal Distribution, the graph is called a normal distribution curve.
The mathematical equation for a normal distribution curve is:
\[y=\frac{1}{\sigma\sqrt{2\pi}}e^{\frac{-(x-\mu)^2}{2\sigma^2}}\]
This formula may look intimidating but in modern statistics tables and technology make easy work of this complicated formula.
The shape and position of a normal distribution curve depend on two parameters, the mean and the standard deviation.
.jpg "Examples of Normal Distributions")