A frequency distribution groups values into ranges and shows how many observations fall within each range. It is like sorting your chickens into weight categories and counting how many end up in each group.
Frequency distributions are typically displayed as bar charts (also called histograms), where:
In the frequency distribution below (Figure 1):
Figure 1. A frequency distribution showing chicken weights. Each bar represents a weight range, and its height shows how many chickens fall in that range.
The Colonel tracked the weights of chickens across multiple breeding seasons. In the distribution above, you can see that most chickens weigh between 5 to 6 pounds, with fewer at the extremes.
Key insight: The shape of this distribution tells us what is "typical" and how much variation exists from chicken to chicken.
To interpret a frequency distribution, we describe two key features:
Let us learn how to identify each of these features!