It seems you might be referring to two specific types of charts: frequency curve (also known as a frequency polygon) and pie chart. Let’s discuss both:
- Frequency Curve (Frequency Polygon):
- A frequency curve, also called a frequency polygon, is a graphical representation of the distribution of data. It is constructed by connecting the midpoints of the tops of the bars in a histogram.
- It is especially useful when you have grouped frequency data (i.e., data that is already grouped into intervals or classes with corresponding frequencies).
- To create a frequency curve:
- Determine the midpoint of each class interval in the histogram.
- Plot these midpoints on the x-axis.
- Plot the frequencies corresponding to each midpoint on the y-axis.
- Connect the points with straight line segments to form the frequency curve.
- Frequency curves provide a visual representation of the shape of the distribution and are useful for comparing multiple datasets or identifying patterns.
- Pie Chart:
- A pie chart is a circular statistical graphic divided into slices to illustrate numerical proportions. The size of each slice is proportional to the quantity it represents.
- Pie charts are most effective when you want to show relative proportions or percentages of a whole.
- To create a pie chart:
- Determine the categories or groups you want to represent.
- Calculate the percentage or proportion of each category relative to the total.
- Draw a circle and divide it into slices proportional to the percentages or proportions calculated.
- Label each slice to indicate its corresponding category.
- Pie charts are commonly used in business reports, presentations, and infographics to visualize categorical data and highlight the relative importance of different components.
- However, they can be less effective than other chart types, such as bar charts, for comparing precise values or showing trends over time.
Here’s a Python code example to create a frequency curve and a pie chart using matplotlib:
import matplotlib.pyplot as plt
# Sample data
categories = [‘A’, ‘B’, ‘C’, ‘D’]
frequencies = [20, 30, 25, 15]
# Frequency curve (frequency polygon)
plt.plot(categories, frequencies, marker=‘o’, linestyle=‘-‘)
plt.xlabel(‘Categories’)
plt.ylabel(‘Frequencies’)
plt.title(‘Frequency Curve’)
plt.grid(True)
plt.show()
# Pie chart
plt.pie(frequencies, labels=categories, autopct=‘%1.1f%%’)
plt.title(‘Pie Chart’)
plt.axis(‘equal’) # Equal aspect ratio ensures that pie is drawn as a circle.
plt.show()
This code will create a frequency curve (frequency polygon) and a pie chart based on the sample data provided. You can adjust the categories and frequencies lists to match your own dataset.