1. List all the types of graphs you are familiar with.
Do Now
List all the types of graphs you are familiar with.

2. Today’s Objective
Represent data in frequency distributions graphically using histograms, frequency polygons, and ogives

3. Histograms
A histogram is a graph that displays the data by using contiguous vertical bars (unless the frequency of a class is zero) of various heights to represent the frequencies of the classes.

4. Use the frequency distribution of the record high temperatures across the 50 states to construct a histogram.
Class Boundaries
Frequency 2 8 18 13 7 1
You guys try!

5. New Types of Graphs Frequency Polygons Ogives
A frequency polygon is a graph that displays the data by using lines that connect points plotted for the frequencies at the midpoints of the classes. The frequencies are represented by the heights of the points.
An ogive is a graph that represents the cumulative frequencies for the classes in a frequency distribution.

6. Use the data to construct a frequency polygon
Class Boundaries
Midpoints
Frequency 2 8 18 13 7 1

7. Use the data to construct an ogive
Class Boundaries
Less than….
Frequency

8. Relative Frequency Graphs
Graphs of relative frequencies instead of frequencies are used when the proportion of data values that fall into a given class is more important than the actual number of the data values that fall into that class.
PERCENTS/PROPORTIONS are more important than RAW DATA.
We find these proportions by dividing the frequency for each class by the total of the frequencies (just like how we found that “percent” column last class!).
The sum of the relative frequencies will always be 1.
Values on the y-axis are in terms of the RELATIVE frequency, not the original frequency.

9. Construct a histogram, frequency polygon, and ogive for the distribution of the miles that 20 randomly selected runners ran in a given week.
Class Boundaries
Frequency 1 2 3 5 4 20
What column do I add for frequency polygons? What about ogives?

10. Distribution Shapes Bell Shape Uniform J-shaped Reverse J-shaped
Right skewed
Left skewed
Bimodal
U-shaped

11. Exit Ticket
1. What different questions could be answered more easily by looking at histograms rather than the list of data?
2. What different questions could be answered more easily by looking at frequency polygons rather than the list of data?
3. What different questions could be answered more easily by looking at ogives rather than the list of data?