9.1 Small Group · Group 2
Second Challenge Form · Non-Routine Extension · Same Standard, New Problems
independent variable · dependent variable · Procedural Fluency · Real-World Applications
- You already can do this. So we go up a level, not up a number: find what is always true, show it a second way, and be ready to defend it with a reason instead of an answer.
- The two quantities are hours of sunlight per day and average plant height after 3 weeks.
- Akela CHOSE where to put each tray, so she chose the sunlight. Sunlight is subject to choice — that makes it the independent variable.
- She did not choose how tall the plants got. Height responded. That makes height the dependent variable.
- Say it as a sentence: plant height depends on sunlight.
- Claire burned 123 Calories on a 30-minute jog and 246 Calories on a 60-minute jog.
- Which did Claire choose — the minutes, or the Calories?
- She chose how long to jog. So time is independent, and Calories burned is dependent.
- Sentence frame: ___ depends on ___ .
- Now prove it: say why that move had to work at all — not just that it did.
- Sentence frame — convince a skeptic: "My method works because ___ . It would stop working if ___ ."
- independent variable (variable independiente) — The quantity that is subject to choice. It does not depend on the other quantity.
- dependent variable (variable dependiente) — The quantity that changes in response to the independent variable.
- depends on (depende de) — One quantity depends on another when changing the first causes the second to change.
- quantity (cantidad) — Something that can be counted or measured.
- relationship (relación) — How two quantities change together.
- Naming the variables backward — calling the responding quantity 'independent' because it is the one the question asks about.
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1 FILL TABLE
Claire burns Calories at a steady rate: 30 minutes burns 123 Calories. Complete the table.
Minutes jogged (independent) Thinking Calories burned (dependent) 30 60 90 ✏️ Scratchpad / Reasoning
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2 MULTIPLE CHOICE
A gym charges $24.95 per month. Which pair correctly names the variables?
- AIndependent: months; Dependent: total cost
- BIndependent: total cost; Dependent: months
- CIndependent: $24.95; Dependent: months
- DIndependent: months; Dependent: $24.95
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
Which of these pairs is NOT a dependent relationship?
- ANumber of pizzas sold and number of employees the shop has
- BNumber of pizzas sold and weekly cost of cheese
- CHours jogged and Calories burned
- DTickets bought and total cost
✏️ Workspace & Solution Steps
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4 OPEN RESPONSE
Describe one situation where time is the independent variable, and a different situation where time is the dependent variable. For each one, say who or what does the choosing.
✏️ Mathematical Justification & Response -
5 OPEN RESPONSE
Here is the result of an experiment: “Water temperature depends on how long the pot has been on the stove.” Working backwards, describe the experiment. What would you choose, what would you measure, and what would the two column headings of your table be?
✏️ Mathematical Justification & Response -
6 ERROR ANALYSIS
Fix our table's thinking
- 1The problem:Claim: “The dependent variable always has the larger values.” Is this claim always, sometimes, or never true?
- 2A classmate at our table answered:Only when both quantities are measured in the same unit
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.