By Mrs. Garcia Wet Heads
Goals Stem and leaf plots Back-to-back stem and leaf plots Objectives/ TEXES standards (included in packet)
MATERIALS and EQUIPMENT -Two 1” by 1” Post-It Notes -Penny -Eye dropper/group -Paper towel (Per Group) -1 Cup of water/group -Markers -Activity Packet -Computer -Student Activity Sheet Teacher -Two large sheets of poster board or large space on a clean black/white board -Computer
PROCEDURES Create a Mental Picture Think of the size of a penny Picture the size of a drop of water • How many drops of water do you think will fit on the head of a penny? • Write your answer down on a sheet of paper.
Organize and Display • Some ways we can organize and display data
Organize and Display Data • Everyone break into groups of 4 • Each group must “sketch” a graph using one of the types of graphs we discussed in our previous lessons • List graphs • Each group will discuss the pros and cons of displaying the data in that form.
Organize and Display Data Stem and Leaf Plot • Stem and Leaf Plots can be a excellent way to organize and display data. • A stem and leaf plot allows for displaying every number in the data set, while still having a visual display of the data.
Stem and Leaf Plot • Out of all of the guesses what was the least amount of drops guessed? • What was the most amount of drops guessed? • These two values represent the data range • This data can be separated into two categories…. • The stem and the leaf
Stem and Leaf Plot • The data displayed vertically (written on the left hand side of a vertical line) are the stems. • Begin with smallest number on top and the largest number on bottom • Place all of the other numbers in between in numerical order.
Stem and Leaf Plot • Once the stem is created we use post it notes to place the individual guesses along the stem horizontally. These are the leafs. • Rearrange each set of leaves in descending order left to right. • This will help you easily identify the mode and the median. • How does this type of graph compare with the others we have discussed?
Compare to other graphs • Drops Stem-and-Leaf Plot • Frequency Stem & Leaf • 5.00 0 . 22333 • 2.00 0 . 66 • 10.00 1 . 1223334444 • 2.00 1 . 55 • 3.00 2 . 344 • 1.00 2 . 5 • 2.00 Extremes (>=32) • Stem width: 10 • Each leaf: 1 case(s)
Instructions • Place the penny on the paper towel and to systematically release drops of water on the head of the penny until it overflows
Do not forget… count each drop, including the drop that “OVERFLOWS!” Instructions Cont’d…
Instructions Cont’d… • Record the “leaf” part of experimental data on Post-it • This data will be displayed on the Stem and Leaf Plot
Back-to-BackStem and Leaf Plot “When two sets of data are displayed on the same stem and leaf plot, it is called a back-to-back stem and leaf plot” We will put our observed data on the left side of stem so that we can see the differences (This image is only an example and does not illustrate actual gathered data)
Again, these leaves should be placed in ascending order . . but from right to left ! Back-to-Back Stem and Leaf Plots Cont’d..
Conclusion • Analyze findings • Go over terminology • Review process of constructing a stem and leaf plot and a back-to-back stem and leaf plot • What are the advantages of displaying data in this form?
Thoughts… • Would your results had been different if you had a different size dropper? • What did you learn in this activity? (use own words and try to include unit terminology) • Provide examples of how Stem and Leaf Plots/Back to Back Stem and Leaf Plots have been used? (research using internet and jot down finding in journal; be prepared to discuss discoveries next class)