Teacher's Guide

Learning objectives

• Explain Data cleaning and Missing value in the context of this lesson.
• Use the worked example to answer the three practice questions with supporting reasoning.
• Complete the activity, evaluate its result, and identify one limitation or possible improvement.

Prerequisites: The preceding grade sequence or equivalent introductory knowledge; begin with a short vocabulary review.

Suggested time: Three to five 45-minute sessions, including activity development and review. Language units need brief repeated spoken practice between sessions.

Teaching sequence

1. Introduce: Present the title as a question or problem. Ask learners what they notice and record two initial ideas without treating them as established facts.
2. Explain: Read the concept section and teach the two vocabulary items. Ask learners to paraphrase the distinction between them using a concrete example.
3. Model: Work through the example. Identify given information, assumptions, and the reason for the result or interpretation. Use a teacher's spoken model for language pronunciation.
4. Apply: Complete the activity individually or in pairs. Require a draft, a check against the task, and a brief revision. Discuss why different justified responses may be acceptable.
5. Retrieve and evaluate: Answer practice and vocabulary questions independently; use the answer key for feedback. Finish with the reflection and an activity rubric.

Assessment and differentiation

The companion CSV contains five retrieval entries: two vocabulary questions and three practice questions. Award one point per accurate answer, accepting equivalent wording that preserves the meaning. Language answers may be oral or written according to the goal. Revisit missed concepts rather than using the score as the only measure of learning.

Assess the activity separately with four criteria, each scored 0-2: correct use of lesson concepts; clear evidence or reasoning; completion of the task requirements; and a useful revision or acknowledged limitation. A 0 indicates missing or unsupported work, 1 indicates partial achievement, and 2 indicates clear achievement. Accept multiple designs, interpretations, and decisions when their reasons meet the criteria.

Support learners with a word bank, annotated example, smaller first step, or partner rehearsal. Extend by changing one assumption or constraint and asking how the result would change. Use invented personal details in financial and social tasks. Optional school character discussion can connect honesty, respect, cooperation, and stewardship to the activity; assess the subject knowledge and reasoning separately.

Student Worksheet

Concept and helping material

Data cleaning checks records for missing values, inconsistent units, duplicates, and obvious input problems. Corrections need a recorded reason; inconvenient observations should not be silently removed. A comparison depends on how data were collected and what the columns mean.

Vocabulary

• Data cleaning: Checking and consistently handling problems in recorded data.
• Missing value: An entry where the intended information was not recorded or is unavailable.

Worked example

A fictional table mixes height in centimeters with height in meters. Convert to a common unit before calculating a mean, keeping a note of the change.

Investigation or design task

Clean a fictional ten-row dataset with two unit errors and one missing value. Document decisions and compare summaries before and after cleaning.

Record your work: State the goal; show your drawing, dialogue, calculation, data, or argument; explain one choice; and describe one check or revision. Identify a limitation rather than claiming your work proves more than it does.

Practice

1. Why convert units before taking a mean?
2. Should an unusual result automatically be deleted?
3. What should accompany a correction?

Vocabulary retrieval

1. Define Data cleaning.
2. Define Missing value.

Reflection

Choose one answer or activity decision. Explain the evidence, calculation, language pattern, or reasoning that supports it. Describe one change of context or assumption that could change your conclusion.

Answer Key

1. Values in different units are not directly comparable.
2. No. It may be valid and needs investigation.
3. A record of the original issue and the reason for the change.

Vocabulary answers are the definitions above and appear in the CSV. Activity and reflection responses vary; use the teacher rubric and require specific reasoning tied to the task. A different supported interpretation is acceptable where the question allows it.

Source Reference

Everything You Need to Ace Computer Science and Coding in One Big Fat Notebook, PDF viewer pages 68-69 (1-based). Conceptual background; the examples, calculations, questions, and activities here are original adaptations. These pages were inspected in the supplied file; viewer numbering may differ from printed numbering. No source worksheets or illustrations are reproduced.

Companion question CSV | Grade guide