1. Histograms, Frequency Polygons Ogives
Section 2-2
Histograms,
Frequency Polygons
Ogives

2. Histograms
The histogram is a graph that displays data by using contiguous vertical bars of various heights to represent the frequencies of the classes.
the x-axis of a histogram represents quantitative i.e. numerical values that are organized in intervals.

3. Frequency Histogram
                                                                                                                     

4. Side by side Histograms

5. Side by side Histograms

7. Bar graph
A Bar Graph (also called Bar Chart) is a graphical display of data using bars of different heights.
The x-axis will display qualitative i.e. categorical data.

9. Bar graph

10. Histograms
Please refer to the states temperatures data from section 2-2.

11. Use your ruler and draw the x and y axes.
Label each of the axes.
Scale each axes carefully.
Represent the class boundaries on the x axis.
Represent the frequency on the y axis.
Using the frequencies as the heights, draw vertical bars for each class.

12. The Frequency Polygon
The frequency polygon is a graph that displays the data by using lines to connect points plotted for the frequencies at the midpoints of the classes. The frequencies are represented by the heights of the points.

14. Frequency Polygon
                                                                                                                     

15. Frequency Polygon Superimposed on a Histogram

16. Constructing a frequency polygon
Step1: Find the midpoints of each class.
Step 2: Draw the x and y axes. Label the x axis with the midpoint of each class. Scale y axis appropriately to plot the frequencies.
Step 3: Using the midpoints for the x values and the frequencies for the y values, plot the points.
Step 4: Connect the plotted points with line segments.

17. The Ogive (pronounced o-jive)
The ogive is a graph that represents the cumulative frequencies for the classes in a frequency distribution.
Ogive frequency graphs are constructed similar to a histogram, with one exception. In this case the y axis represents the cumulative frequency.

18. Cumulative Frequency

19. Relative frequency graphs
Relative frequency graphs are constructed similar to a histogram, with one exception. In this case the y axis represents the relative frequency.

20. Relative Frequency Histogram

21. Cumulative Relative frequency graphs
Relative cumulative frequency graphs are constructed similar to a histogram, with one exception. In this case the y axis represents the cumulative relative frequency.

22. Cumulative Relative Frequency
                                                                                                                      

23. Graphing Calculator Page 61 Page 62
Constructing histograms from raw data
Page 62
Constructing a Histogram from a frequency distribution table

24. Exercises 2-2, page 61 starting with # 1 every other odd problem.
Homework:
Read pages
Applying Concepts 2-2 page 60
Make sure to answer all questions completely.
Graphs must be done on graph paper; make sure to use a ruler.
Homework
Exercises 2-2, page 61 starting with # 1 every other odd problem.