This topic introduces the basic concept of Normal Distribution, which is the most common type of Continuous Probability Distribution.

Lesson 1 of 3: Learning Outcomes

At the end of this lesson, you should be able to:

1. Identify characteristics of a Normal distribution by using its characteristics such as the mean, standard deviation, median and mode.

Lesson 2 of 3: Introduction to Normal Distribution (10 mins)

Continuous Probability Distribution

• A Continuous Random Variable is one that has infinitely many values.

• These values are measured on a continuous scale in such a way that there are no gaps or interruptions. Example: GPA score, weight or height.

• Therefore, we represent a Continuous Probability Distribution by a curve.

• The Normal Distribution (commonly called ‘bell curve’) is the most important and most widely used continuous probability distribution in statistics.

  

Examples of Normal Distribution

Normal Probability Distribution

A normal distribution is a continuous probability distribution for a continuous random variable, x.  The graph of a normal distribution is called the normal curve.

Properties of a Normal Distribution:

1. The mean, median, and mode are equal.
2. The normal curve is bell-shaped and symmetric about the mean.
3. The total area under the curve is equal to 1.
4. Approximately 95% of distribution lies within 2 standard deviation of mean (2 σ rule)

• Different Standard Deviations
• Different Means

Additional Resources