2.2 Small Group · Group 1
Second Practice Form · Re-Teach, Homework or Retake · Same Standard, New Problems
Display Data with Histograms · Histogram · Procedural Fluency · Real-World Applications
- A histogram is a bar graph that groups numbers into equal ranges called intervals. The height of each bar is the frequency: how many values fall in that interval. The bars touch because the intervals are continuous. We'll walk through a worked example, try one together, then you'll try a few with hints right there when you need them.
- My data: 3, 7, 12, 15, 18, 24. I will use intervals of 10: 0–9, 10–19, 20–29.
- Interval 0–9: the values 3 and 7 fit, so the frequency is 2.
- Interval 10–19: the values 12, 15, and 18 fit, so the frequency is 3.
- Interval 20–29: only the value 24 fits, so the frequency is 1.
- Now I draw three bars with heights 2, 3, and 1, touching each other. The tallest bar (10–19) is where most values are.
- Display Data with Histograms (Representar datos con histogramas) — Group numerical data into intervals and show each interval's frequency with a bar.
- Histogram (Histograma) — A bar graph that groups data into equal ranges. The bars touch.
- Frequency (Frecuencia) — How many times a value shows up.
- Interval (Intervalo) — A range of numbers used to group data.
- Distribution (Distribución) — How the data is spread out.
- Variability (Variabilidad) — How spread out the numbers are.
- A common mistake in Display Data: Histograms is counting a boundary value in two intervals at once — for example, putting the value 10 in both the '0–9' bin and the '10–19' bin. Each data value belongs to exactly ONE interval. Before you submit, add up all your frequencies and check that the total matches the number of data values you started with.
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1 MULTIPLE CHOICE
A histogram bar for the interval 20–29 reaches a height of 7. What does the 7 tell you?
- AThe largest value is 7
- BThere are 7 intervals
- CThe interval is 7 wide
- D7 data values fall between 20 and 29
✏️ Workspace & Solution Steps
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2 MULTIPLE CHOICE
A histogram of test scores shows: 50–59: 2, 60–69: 5, 70–79: 10, 80–89: 8, 90–99: 3. Which interval has the most students?
- A90–99 with 3 students
- B70–79 with 10 students
- C80–89 with 8 students
- D60–69 with 5 students
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
A histogram of goals-per-game shows: 0–1: 9 players, 2–3: 6, 4–5: 3, 6–7: 1. What shape is this distribution?
- APerfectly symmetric
- BFlat / uniform (all bars equal)
- CSkewed right (most players low, tail toward high values)
- DSkewed left (most players high, tail toward low values)
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
Data: 4, 8, 9, 12, 14, 15, 17, 18, 19, 22, 24, 27, 31, 33. How many values fall in the 10–19 interval?
- A9
- B5
- C6
- D3
✏️ Workspace & Solution Steps
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5 ERROR ANALYSIS
Spot the Counting Mistake
- 1Data (points per game):3, 7, 11, 13, 16, 22
- 2Intervals:0–9, 10–19, 20–29
- 3Frequency count:0–9: 2, 10–19: 2, 20–29: 1
- 4Conclusion:So the histogram bars have heights 2, 2, and 1.
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
6 ERROR ANALYSIS
Spot the Interval Mistake
- 1Data (assists per game):1, 4, 6, 9, 12, 15, 18
- 2Intervals the student chose:0–5, 6–10, 12–18
- 3Frequency count:0–5: 2, 6–10: 2, 12–18: 3
- 4Conclusion:The student drew three bars and said the histogram was complete.
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Writing Task: Justify why your mathematical solution is accurate and complete.