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Subject: Mathematics
Semester: 2
Period: 6
Week: 32
WEEK 32
Class: Grade 9
Age: 14 years
Duration: 40 minutes of 5 periods
Subject: Mathematics
Topic: Stem-and-Leaf Plot
Focus: Organizing and Interpreting Data Using Stem-and-Leaf Plots
SPECIFIC OBJECTIVES:
By the end of the lesson, pupils should be able to:
- Define a stem-and-leaf plot and explain its importance in organizing data.
- Organize data into a stem-and-leaf plot.
- Read and interpret information from stem-and-leaf plots.
- Construct stem-and-leaf plots from class test scores or real-life data.
- Apply stem-and-leaf plots in practical classroom data collection activities.
INSTRUCTIONAL TECHNIQUES:
- Question and answer
- Guided demonstration
- Practical classroom activity
- Group exercises and discussion
INSTRUCTIONAL MATERIALS:
- Worksheets with raw data sets
- Whiteboard and marker
- Flashcards with numbers
- Graph paper (optional)
- Rulers and pencils
PERIOD 1 & 2: Introduction to Stem-and-Leaf Plot
PRESENTATION:
|
Step |
Teacher’s Activity |
Pupil’s Activity |
|
Step 1 – Anticipation (Warm-up) |
Teacher shows an unorganized data set of test scores and asks: “How can we organize this data so it is easier to read?” |
Pupils suggest ways of organizing data (table, chart, graph). |
|
Step 2 – Building Knowledge (Explanation) |
Defines stem-and-leaf plot: a method of displaying data where each number is split into a “stem” (leading digit) and a “leaf” (last digit). Explains importance: easy visualization, retains original data, shows shape of distribution. |
Pupils listen and take notes. |
|
Step 3 – Demonstration |
Example: Test scores: 23, 25, 27, 31, 32, 35 |
|
|
Stem |
Leaf |
|
|
2 |
3,5,7 |
|
|
3 |
1,2,5 |
Pupils observe demonstration. |
|
Step 4 – Consolidation (Practice) |
Teacher gives another data set: 41, 42, 45, 46, 48. Guides pupils to create stem-and-leaf plot. |
Pupils construct the plot individually or in pairs. |
NOTE ON BOARD:
- Stem = all digits except the last; Leaf = last digit
- Example: 23 → Stem = 2, Leaf = 3
- Organize all numbers by stems in ascending order
EVALUATION (5 exercises):
- Create a stem-and-leaf plot for: 12, 15, 17, 21, 23, 25.
- Construct a stem-and-leaf plot for: 34, 36, 39, 41, 42.
- Data: 11, 13, 14, 16, 18 → plot stem-and-leaf.
- Explain the advantage of using a stem-and-leaf plot.
- Create a stem-and-leaf plot for: 22, 25, 28, 31, 33.
CLASSWORK (5 questions):
- Data: 14, 16, 18, 20, 23 → stem-and-leaf plot.
- Construct stem-and-leaf plot for: 37, 39, 41, 44, 46.
- Plot: 51, 52, 55, 57, 59.
- Explain how the stem-and-leaf plot helps in analyzing data.
- Create stem-and-leaf plot for: 12, 14, 16, 18, 20.
ASSIGNMENT (5 tasks):
- Collect the ages of 10 classmates and construct a stem-and-leaf plot.
- Create a stem-and-leaf plot for: 31, 33, 35, 37, 39.
- Make a stem-and-leaf plot for your family members’ ages.
- Construct stem-and-leaf plot for test scores: 15, 17, 18, 19, 20.
- Write one real-life example where stem-and-leaf plots are useful.
PERIOD 3 & 4: Reading and Interpreting Stem-and-Leaf Plots
PRESENTATION:
|
Step |
Teacher’s Activity |
Pupil’s Activity |
|
Step 1 – Anticipation |
Teacher presents a completed stem-and-leaf plot and asks: “What can we learn from this data?” |
Pupils analyze and answer. |
|
Step 2 – Building Knowledge (Explanation) |
Explains how to: identify highest/lowest values, mode, median, and patterns in data from stem-and-leaf plots. |
Pupils take notes. |
|
Step 3 – Demonstration |
Example: Stem Leaf |
Pupils practice reading the plot. |
|
|
|
|
|
2 3,5,7 |
||
|
3 1,2,5 Smallest value = 23, largest = 35 Mode = 25 |
||
|
Step 4 – Consolidation (Practice) |
Teacher gives a plot and asks pupils to find smallest, largest, median, mode |
Pupils work individually or in pairs. |
EVALUATION (5 exercises):
- Given plot:
4 | 1,3,5
5 | 0,2,4
- Find smallest and largest values
- Find mode of above data
- Identify median
- Explain what the plot reveals about the data
- Draw conclusion about distribution
CLASSWORK (5 questions):
- Stem | Leaf:
3 | 2,5,6
4 | 0,2,5 → smallest, largest, median, mode?
- Data analysis: interpret plot
1 | 2,4,6
2 | 0,3,5
- What is the range?
- What is the mode?
- Describe the distribution (clustered, uniform, etc.)
PERIOD 5: Constructing Stem-and-Leaf Plots from Class Test Scores / Real-Life Data
PRESENTATION:
|
Step |
Teacher’s Activity |
Pupil’s Activity |
|
Step 1 – Anticipation |
Teacher asks pupils to collect real-life data (heights, scores, ages). |
Pupils gather data. |
|
Step 2 – Building Knowledge (Explanation) |
Teacher demonstrates constructing a stem-and-leaf plot from collected data (e.g., 12, 14, 15, 18, 20, 22). |
Pupils observe and take notes. |
|
Step 3 – Guided Practice |
Pupils construct plots from teacher-provided data. |
Pupils practice in groups. |
|
Step 4 – Independent Practice |
Pupils create stem-and-leaf plots from their collected data and interpret. |
Pupils work individually, then present results. |
EVALUATION (5 exercises):
- Construct a stem-and-leaf plot for scores: 12, 15, 17, 18, 19, 20, 22.
- Find median and mode of the above.
- Construct stem-and-leaf plot for: 23, 25, 27, 29, 30, 32.
- Find smallest, largest, median, mode.
- Interpret the distribution.
CLASSWORK (5 tasks):
- Construct plot for scores: 11, 14, 16, 18, 19.
- Find median and mode.
- Construct plot for scores: 20, 22, 25, 27, 29.
- Find range, median, mode.
- Write a short paragraph interpreting the data.
ASSIGNMENT (5 tasks):
- Collect 10 classmates’ scores and make a stem-and-leaf plot.
- Identify median, mode, range.
- Construct plot for daily temperatures over a week.
- Create a stem-and-leaf plot from your family members’ ages.
- Write one real-life scenario where this plot is helpful.