Frequency Polygon

Topic: Frequency Polygon
Student Name: Kubra
Class: B.Ed. 2.5
Project Name: “Young Teachers' Professional Development (TPD)"
"Project Founder: Prof. Dr. Amjad Ali Arain
Faculty of Education, University of Sindh, Pakistan

1. FACULTY OF EDUCATION ELSA QAZI CAMPUS PREPAIRED BY : KUBRA SEAT NO: 28 TOPIC: Frequency polygon ASSIGNED BY: DR. AMJAD ALI ARAIN

2. Objecti v e: To represent data in frequency distributions graphically using histograms, frequency polygons, and ogives. a] What % of Americans find life dull? b] What % of Americans are color blind? c] How many gallons of soda does the average American drink during a year?

3. Graphs Purpose: To display data to viewer in pictorial form Used to: Describe or analyze data Discuss an issue Reinforce a critical point Summarize a data set Discover a pattern or trend over time Useful in getting the attention of the audience

4. Three Most Common Types of Graphs Histogram Frequency Polygon Cumulative Frequency Graph (Ogive)

5. Hi s togram histogram : graph that displays the data by using contiguous vertical bars (unless the frequency of a class is 0) of various heights to represent the frequencies of the classes To construct a histogram: Draw and label the x and y axes. Represent the frequency on the y-axis and the class boundaries on the x-axis. Using the frequencies as heights, draw vertical bars for each class.

6. Histogram Example

7. Frequency Polygon frequency polygon : graph that uses lines that connect points plotted for the frequencies at the midpoints of the classes; frequencies are represented by the heights of the points To construct a frequency polygon: Find the midpoints of each class Draw the x and y axes. Label the x-axis with the midpoint of each class then use a suitable scale for the frequencies on the y-axis. Using the midpoints for the x values and the frequencies as the y values, plot the points. Connect adjacent points with line segments. Draw a line back to the x-axis at the beginning and end of the graph (where the next midpoints would be located)

8. Frequency Polygon Example 20 18 16 14 12 10 8 6 4 2 102 107 112 117 122 127 132 137

9. The Ogive (Cumulative Frequency Polygon) ogive : graph that represents the cumulative frequencies for the classes in a frequency distribution To construct an ogive: Find the cumulative frequency for each class Draw the x and y axes. Label the x-axis with the class boundaries. Label the y-axis with an appropriate frequency (don’t use actual frequency numbers-yields uneven intervals or classes) Plot the cumulative frequency at each upper class boundary Starting with the first upper class boundary, connect adjacent points with line segments. Extend the graph to the first lower class boundary on the x-axis.

10. Constructing Statistical Graphs- General Procedures Draw and label the x and y-axes Choose a suitable scale for the frequencies or cumulative frequencies, and label it on the y- axis. Represent the class boundaries for the histogram or ogive, or the midpoint for the frequency polygon, on the x-axis. Plot the points and then draw the bars or lines.

11. Distribution Shapes Bell-shaped: single peak and tapers off at either end Uniform: basically flat or rectangular J-Shaped: Few data values on the left side and increases as one moves to the right Reverse J-Shaped: Opposite of J-Shaped Right-Skewed: Peak of the distribution is to the left and the data values taper off to the right (Positively skewed) Left-Skewed: Data values are clustered to the right and taper off to the left (Negatively skewed) Bimodal: Two peaks of the same height U-Shaped: Peaks at both ends and decreases toward middle

12. #1 - Histogram

13. #1 – Frequency Polygon

14. #1 - Ogive

15. #3 - Histogram

16. #3 – Frequency Polygon

17. #3 - Ogive

18. #7 – Histogram 1

19. #7 – Hisotgram 2

20. #15 – Frequency Table

21. #15 - Histogram

22. #15 – Frequency Polygon

23. #15 – Ogive

24. Thanks your sir