Graphing Data

Overview

In this lesson (Lesson 18 of 20), students focus on representing data visually using bar graphs and line graphs. They interpret graphs and connect visual features (axes, intervals, labels and trends) to the story the data tells.

Learning intentions

Students will:

• select an appropriate graph type (bar or line) for a given data situation
• create a bar graph and a line graph using correct axes, scales and labels
• interpret key features of graphs, including comparisons and changes over time

Success criteria

Students can:

• draw axes, label them clearly, and use a sensible scale for the data
• choose bar graphs for “different categories” and line graphs for “change over time”
• read values from graphs and explain what the trend or comparison shows
• check their graph for accuracy by reviewing plotted points/bars against the table of values

Curriculum links

• Statistics — plan and conduct statistical investigations involving samples, using ethical and fair methods to make inferences; report findings acknowledging uncertainty - Statistics — compare variations in distributions and proportions from samples; recognise the effect of sample size on variation - Algebra (data-to-graph skills) — use graphical representations to support solution-checking processes (visual reasoning that supports later graphical/algebraic work) ## Lesson structure (30 minutes)

1. 0–5 min · Hook and discussion. Teacher shows two mini scenarios: (A) “number of students with different favourite snacks” and (B) “temperature each morning for 5 days”, and asks which graph fits each scenario and why. Student pair-thinks (individually for 1 student) and answers verbally, identifying “categories” vs “time”.

2. 5–12 min · Direct teach: bar vs line graphs. Teacher draws a quick reference on the board: bar graphs use separate bars for categories; line graphs use connected points to show change over time; explain essentials: title, axes, scale, labels, and units. Student copies a short checklist and completes one guided choice: “Should this be a bar or a line graph?” for a third scenario.

3. 12–20 min · Guided practice: bar graph from a table. Teacher provides a small table of category counts (e.g., “Favourite fruit” for 20 students: Apple 8, Banana 6, Orange 4, Other 2) and demonstrates plotting: choose vertical axis for frequency, horizontal axis for categories, ensure equal spacing and clear bar width. Student draws the bar graph on prepared grid paper, using a teacher-provided scale suggestion; teacher checks accuracy by asking the student to read back the value of one category.

4. 20–27 min · Guided practice: line graph from time data. Teacher provides a time table (e.g., “Phone charging percentage each hour” at 0h: 100, 1h: 92, 2h: 85, 3h: 78) and models: set horizontal axis as time, vertical axis as measurement with scale, plot points, then join with a straight or smooth line only if the change is continuous (for this level, straight-line segments are acceptable). Student creates the line graph and answers one interpretation question: “At what time did the largest drop happen?” using the plotted points.

5. 27–30 min · Exit check and reflection. Teacher gives two quick interpretation prompts: (1) “Which category has the highest frequency?” from the bar graph and (2) “Is the trend increasing or decreasing?” from the line graph. Student responds and also states one graphing improvement they would make (e.g., clearer labels or better scale).

Resources

• Grid paper (bar and line graph templates or blank axes)
• Pre-written category table and time table (printed or on board)
• Markers/coloured pencils
• Ruler for drawing straight axes
• Small digital tool option: spreadsheet/graphing app for showing example graphs (optional if available)
• Checklist card: title, axes, labels, scale, units, correct graph type

Assessment

• Teacher observation during graphing: correct choice of graph type and accurate plotting
• Oral questioning: student explains why bar/line graphs are appropriate and interprets one value/trend
• Exit prompts (quick verbal or written): highest bar category and direction of trend

Differentiation

• Support: provide a partially drawn set of axes for both graphs and a suggested scale (e.g., frequency scale increments of 2 or 1); use sentence starters such as “A line graph is best because…”
• Support: allow the student to use a ruler and colour-code axes labels.
• Extension (only if time): ask the student to suggest a better scale to reduce awkward numbers and to improve readability, or to add a short sentence interpreting the real-life meaning of the trend.
• Check understanding for accuracy: if the student plots one point incorrectly, pause and compare the point position to the table value and axis scale.