- Describe the graph of a data set using its shape, center, spread, and outliers
Describing Center and Spread
To describe the pattern in a distribution of a quantitative variable, we describe more than the shape. The center and spread are two other important features of the distribution of the data set.
center
The center describes the location of the middle of the distribution.
The center is a number that describes a typical value from the data set.
For example, the center could be the point in the distribution where about half of the observations are below it and half are above it.
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spread
The spread is a measure of how much the values in a data set tend to differ or vary from one another.
Variability is another word for spread.
One way we can measure the spread is by finding the minimum and maximum values in the data and calculating the difference between them. This difference is called the range.