Plotting Data using | Class 12 Informatics Practices Notes

4.4.3 Plotting Histogram

Histograms are a type of column chart used to represent the frequency distribution of numerical data by grouping data points into bins or intervals. Each bar's height corresponds to the number of data points within that bin. The section explains how Pandas plot(kind='hist') automatically selects bin sizes based on data spread but also allows manual specification of bins. An example with height and weight data demonstrates plotting a histogram for multiple numeric columns. Customization options include changing edge color, line style, line width, fill property (filled or empty bars), and hatch patterns for bar fills. The section also introduces the concept of open data and demonstrates plotting histograms using a real dataset of India's annual minimum and maximum temperatures from 1901 to 2017, downloaded from an open data platform. A program example shows plotting histograms for single and multiple columns and customizing axes labels and titles. Another example overlays a frequency polygon on the histogram to better visualize frequency distribution.

📊 Diagram: Figure 4.9: A histogram as output of Program 4-8; Figure 4.10: Customised histogram as output of Program 4-9; Figure 4.11: Histogram for 'ANNUAL - MIN' and 'ANNUAL - MAX'; Figure 4.12: Histogram for 'ANNUAL - MIN'; Annual Min Temperature plot (1901 - 2017)

🔗 Connection: This section leads to the next on plotting scatter charts to visualize relationships between two variables.