1. AP Statistics Friday September 4
Check reading guide, 7-11-doubles for bookwork.
Quiz
Ogives and Timeplots
Homework:
Read pages 69-74
Reading Guide Page 2 #1-5
Book problems 1.14 a,b and 1.15

2. Ogives
Named because of its resemblance to the shape of architectural molding known as ogee.
Used to determine how many data values lie above or below a particular value in the dataset.

3. Ogives (relative frequency graphs) construction Follow along with example on pg. 61
Start by making the relative frequency table.
Decide on class intervals (like you do with a histogram), and make a table with 5 columns:
Class, Frequency, Relative Frequency, Cumulative Frequency, and Relative Cumulative Frequency
To find relative frequency, divide the class frequency by the total and convert to a percent.
To find cumulative frequency, add the counts in the frequency column that fall in or below the current class interval.
To find relative cumulative frequency, divide the cumulative frequency by the total number of individuals.

4. Once you have the relative cumulative frequencies, graph them.
Ogives (relative frequency graphs) construction Follow along with example on pg. 61
Once you have the relative cumulative frequencies, graph them.
The y-axis will always go from 0%-100%.
The x-axis will be scaled according to your class intervals.
Plot the point for each class interval on the left endpoint of the NEXT interval.

5. Timeplots
Whenever data are collected over time, plot observations chronologically.
Used when change occurs over time.
Other graphical methods do not account for change over time.
Common Example: Stock prices