14. Normal Probability Distributions
On this page...
- Properties of a normal distribution
- Area under the normal curve
- Standard normal distribution
- Percentages of the area under standard normal curve
- The z-Table
- Application - stock market
Notation
We use upper case variables (like X and Z) to denote random variables, and lower-case letters (like x and z) to denote specific values of those variables.
The Normal Probability Distribution is very common in the field of statistics.
Whenever you measure things like people's height, weight, salary, opinions or votes, the graph of the results is very often a normal curve.
The Normal Distribution
A random variable X whose distribution has the shape of a normal curve is called a normal random variable.