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Teacher guide — Grade 8, Unit 1: What is data?

Time: 3 lessons + project (about 5 periods). Track: A (no-code).

# Lesson Time
1 Data are everywhere 40–45 min
2 Who collects Nepal's data? 40–45 min
3 Reading a table 40–45 min
P Unit project: My data portrait 2 periods

Before you start

  • Materials: 20 cards per group (see worksheets/w1-sort-cards.md), printed table (worksheets/w2-read-a-table.md), pencils.
  • Read docs/pedagogy/lesson-anatomy.md and docs/pedagogy/ai-use-policy.md.

If you have no computers / no internet

All eight units run on paper, calculators and the blackboard. Computers are optional (spreadsheet or CODAP, https://codap.concord.org); every activity below has a paper version.

Common misconceptions

  • "Ward number is a number so I can average it." It is a label (categorical): arithmetic on it has no meaning.
  • Confusing a row (one student) with a column (one variable).
  • Thinking data must be numbers; names and colours are data too.

Differentiation

  • Support: give a partially filled table / sentence starters; pair with a data-steward role.
  • Stretch: ask "what would change your conclusion?" and "who is missing?"

Answer key (check questions)

Lesson 1: Data are everywhere 1. Is 'favourite colour' numerical or categorical?
Answer: Categorical. 2. Give one numerical variable about your school.
Answer: Any measured/counted one, e.g. number of students in Grade 8. 3. Why is a ward number categorical even though it looks like a number?
Answer: It is a label; adding or averaging ward numbers means nothing.

Lesson 2: Who collects Nepal's data? 1. Which organisation runs the national census?
Answer: The National Statistics Office (NSO) of Nepal. 2. Why should we ask 'who collected this data and why'?
Answer: Purpose and method affect what is included and whether we can trust it. 3. Name one thing a school could measure itself.
Answer: e.g. daily attendance, rainfall in a rain gauge, travel time.

Lesson 3: Reading a table 1. A table has columns: student_code, travel_mode, travel_minutes, height_cm. How many variables?
Answer: 4 (student_code is an ID; 3 are real variables). 2. Which of those are numerical?
Answer: travel_minutes and height_cm. 3. What does one row represent?
Answer: One student.

Assessment

Starter quiz each lesson (3 questions, one recalling the previous lesson); unit quiz in quiz.yml; project marked with the rubric in docs/pedagogy/assessment.md; 2-minute oral check per group.

Alignment

Extends the Grade 8 compulsory Maths statistics chapter (pie chart, mean, median, mode) with question-forming, data collection and interpretation.

Answers: practice exercises

  1. (a) categorical (b) numerical (c) categorical (d) numerical (e) categorical: a label (f) numerical.
  2. (b) measurement · (d) count · (f) measurement.
  3. (a) Ministry of Culture, Tourism and Civil Aviation / Department of Tourism (also Nepal Tourism Board); (b) Department of Hydrology and Meteorology; (c) Nepal Rastra Bank (NSO also publishes price indices).
  4. Three formats and two calendars: they cannot be compared or averaged. Better: "Age in completed years: ___" or ask for date of birth in one stated calendar (BS or AD) and calculate.
  5. Check: codes not names; one row per person; units written (cm, minutes, years).
  6. Marks can be averaged; divisions cannot (the "average" of First and Second Division is meaningless). Divisions do have an order (Distinction > First > Second), so they are ordinal categorical.
  7. Any two: why students were absent; who arrived late; whether students were learning; attendance in other classes; who left early.
  8. "Who collected it?" and "When?" first: the census 2021 final count was about 29.2 million; "30 million" may be a projection, a rounded figure or an error. Then "how" (census or estimate?).
  9. No. 0 °C is not "no heat"; it is where water freezes. Ratios only make sense when zero means "none" (for example 20 mm of rain is twice 10 mm). This stretch idea (interval vs ratio scales) is enough at this level.
  10. Accept any form with ≥2 numerical (hours per day, number of apps, age when first used a phone) and ≥2 categorical (phone owner: self/family/none, main use: study/games/social), units given, no names.

Real-data exercises: notes

  • R1 One row = one year. Columns: year (time label; treat as categorical/ordered here), arrivals by air, arrivals by land, total arrivals (counts, persons), earnings (money, check unit on the page: usually NPR or US$ in thousands/millions). Source: MoCTCA via Open Data Nepal, collected at airports and border points. Can answer: "Did arrivals grow between 2001 and 2014?" Cannot answer: "Why did they fall?" or anything after 2014.
  • R2 Population and households are numerical counts; district and province are categorical. Mother tongue is categorical with more than 100 categories (124 languages were reported in 2021; confirm on the results page). Handle sensitive variables (caste, religion) as "describing groups", never ranking them.
  • R3 Good for a homework check-in; ask two students to read out one example each.