1. Relative Cumulative Frequency Graphs
AP Statistics

2. How to construct an ogive (relative Cumulative Frequency Graph)
Step 1: Decide on class intervals and make a frequency table just as in making a histogram. Add three columns to your frequency table: relative frequency, cumulative frequency, and relative cumulative
frequency
-To get the values in the relative frequency column, divide the count in each class interval by the total number of the frequency. Multiply by 100 to convert to a percentage.
-To fill the cumulative frequency column, add the counts in the frequency column that fall in or below the current class interval.For the relative cumulative frequency column, divide the entries in the cumulative frequency column by the total number of individuals.
Step 2: Label and scale your axes and title your graph. Label the horizontal axis “Age at Inauguration” and the vertical axis according to your choice of class intervals and the vertical axis from 0% to 100%
Step 3: Plot a point corresponding to the relative cumulative frequency in each class interval at the left endpoint of the next class interval the last point you plot should be at a height of 100%

3. Lets refer back to example 1.6 done yesterday in class.
How can you do this quickly? Make a histogram on your calculator. We will use yesterday’s histogram.

4. Construct your Table by ANALYZING your Histogram
Class Frequency Relative Frequency Cumulative Frequency Relative Cumulative Frequency
/43= or 4.7% /43= or 4.7%
/43= or 14% /43= or 18.6%
/43= or 30.2% /43= or 48.8%
/43 = or 27.9% /43= or 76.7%
/43= or 16.3% /43= or 93%
/43= or 7% /43= or 100%

5. The following is a relative cumulative frequency plot of the US presidents’ ages at inauguration
Class Frequency Relative Frequency Cumulative Frequency Relative Cumulative Frequency
/43= or 4.7% /43= or 4.7%
/43= or 14% /43= or 18.6%
/43= or 30.2% /43= or 48.8%
/43 = or 27.9% /43= or 76.7%
/43= or 16.3% /43= or 93%
/43= or 7% /43= or 100%

6. In the following (a) shows how we locate Bill Clinton’s age in the distribution and (b) shows how to determine the 60th percentile and the center of the distribution.

7. QUIZ REVIEW
Know how to construct Bar Graphs, Dot Plots, Stem Plots, Pie Charts, histograms
Know how to read ogives (relative cumulative frequency graphs).
Know the difference between a categorical variable and a quantitative variable
Be able to describe a distribution (remember this means to give the shape, center AND spread)