2. Used to rank-order and arrange data into groups Used to detect patterns and extreme data values Useful when data are gathered for general interest and observation of subjects (no specific questions in mind) Sometimes used to make frequency tables easier In histograms, we lose specific data. Stem-and-leaf displays allow us the ability to retrieve original data.

3. 1.Divide the digits into two parts (stem → left, leaf → right) 2.Align the stems in a vertical column from smallest to largest. Draw a vertical line to the right of the stems. 3.Place leaves in the appropriate stem row and order from least to greatest. 4.Use a label to show the meaning and units of the stem and leaf. i.e. Stem Leaves 0 268 1 2 represents 12 packages 1 245 2 016 Example #5 p.57

4. How do we divide the stem and leaves? *Guided exercise #4 How to Split a stem: When a stem has many leaves, split the stem into multiple lines. For two lines per stem, use 0 to 4 for one line and 5 to 9 for the next. i.e. Stem Leaves 1 0 0 1 2 2 2 2 3 3 4 4 1 5 5 5 6 7 8 8 9 9 2 1 2 6 9

5. Back-to-Back Stem Plot Useful when comparing similar data from two populations Leaf 1 Stem Leaf 2 1 0 2 0 0 2 3 3 1 1 3 2 2 4 0 3 5 2 0 represents 25 for Leaf 1 and 20 for Leaf 2

6. p. 61- 64 #1, 2, 5, 10