The Normal Distribution

Normal Distribution

A continuous, symmetric, bell-shaped distribution of a variable.

Standard Normal Deviation

A normal distribution with a mean of 0 and a standard deviation of 1.

Symmetric Distribution

When data values are evenly distributed about the mean, a distribution is said to be?

Positively or right-skewed distribution

When the majority of the data values fall to the left of the mean, a distribution is said to be?

Negatively or left-skewed distribution

When the majority of the data values fall to the right of the mean, the distribution is said to be?

Properties of a normal distribution

1. A normal distribution curve is bell shaped. 2. The mean, median, and mode are equal and are located at the center of the distribution. 3. A normal distribution curve is unimodal.(one mode) 4. The curve is symmetric about the mean. 5. The curve is continuous. 6. The curve never touches the x-axis. 7. The total area under a normal distribution curve is equal to 1.00, or 100%. 8. The area under the part of a normal curve that lies within 1 standard deviation of the mean is approximately 0.68, or 68%; within 2 standard deviations, about 0.95, or 95%; and within 3 standard deviations, about 0.997, or 99.7%.