Clue 1: Orient yourself
What is deliberately changed?
Use the labels and the picture's left-to-right, near-to-far, or before-and-after order. Name only what you can point to.
The question
What is deliberately changed?
Why it matters: Clinical recommendations affect real children and families. Fair comparisons, bias control, ethical limits, and honest uncertainty keep a promising result from becoming a harmful claim. Today you practice the professional reasoning behind that work: A falsifiable hypothesis links a defined change to a defined outcome and states what would count against it.
On your WebXam
Identifying the independent variable, dependent variable, and control group
For life
To find the cause, change one thing and watch what changes.
Principle: Same look, different cause
Five principles we return to
Having it is not using it
Same instructions, different switches
Same look, different cause
Change one thing and watch
Boss or doorman?
Decides the result or only allows it
Held down, not gone
Remove the brake and it returns
Many roads, one ending
One result can begin many ways
Try the everyday version first
A crash-test prediction names the change, the sensor, and the failure result
A useful crash test states what will change, what sensor will measure, and which result would count as failure. That plan can be checked before the test begins.
Do not jump to the biology yet. Treat the picture as a small system. Track its parts, follow one change at a time, and keep more than one explanation open until the picture supplies a way to separate them.
Clue 2: Trace one change
Which sensor records the result?
Follow one object, stage, or path. Point to the first place where the situation changes instead of jumping to the ending.
Clue 3: Keep the cause open
Which result would make the prediction fail?
List more than one explanation that still fits. Name the extra observation that would help you separate those possibilities.
Now inspect the illustration
Work from the visible evidence. A useful answer names the part of the picture that supports it and leaves unknown causes open.
- 1What is deliberately changed?
- 2Which sensor records the result?
- 3Which result would make the prediction fail?
Tier 1 check
Finish with the everyday model
Use the everyday picture to answer today's question in plain words: What is deliberately changed?
You can complete today's required check without opening the technical details below.
Ready for the real names? Optional tier 2
Technical rules and limits
Rule 1: Change one defined independent variable.
Rule 2: Measure one defined dependent outcome.
Rule 3: Write a result that could count against the prediction.
Where the analogy stops: Human clinical studies cannot control every feature as tightly as a mechanical crash test.
Carry the previous idea forward
A researchable question names a population, a factor or intervention, a comparison, and a measurable outcome.
Today's technical takeaway
A falsifiable hypothesis links a defined change to a defined outcome and states what would count against it.
Now map the same rules onto biology
Convert the PICO question into a testable timing hypothesis
Seat design
Repair timing, the independent variable
Force sensor
VPI at age 5, the dependent outcome
Failed prediction
No lower VPI in the earlier group
Educational illustration, not a clinical photograph or a patient-specific study plan. Use the supplied evidence cards and claim ceiling.
Mateo's case file: evidence supplied in this lesson
EXP02-E1
The proposed study compares repair at 6 months with repair at 12 months.
Why it matters: Repair timing is the factor that differs between groups.
EXP02-E2
The primary outcome is VPI status at age 5.
Why it matters: The outcome must be measured the same way in both groups.
EXP02-E3
A valid hypothesis can be challenged by equal or higher VPI in the 6-month group.
Why it matters: The prediction is falsifiable rather than protected from failure.
Make the clinical decision
You are the methods lead completing the hypothesis card.
A draft says, 'Earlier surgery will help somehow,' and the team must decide whether it can guide a study.
ARewrite it with timing, VPI at age 5, and a result that would oppose the prediction.
BKeep it because every positive change can count as success.
CRemove the comparison group so no result can disagree.
Choose the revision and identify the independent variable, dependent variable, and falsifying result.
Evidence required
EXP02-E1 + EXP02-E2 Claim ceiling
You may state a testable prediction. You may not claim the hypothesis is true before the comparison.Go deeper Optional tier 3
Everything required for today is above. Open these only if you want the explainer, source trail, or download files.
The everyday model and Tier 1 check are the complete required path for this lesson.
Use these checks to keep your place. They are not turned in through the portal.
Check off as you finish
- Worked through the everyday picture and answered its three questions.
- Completed the Tier 1 check in plain words.
Turn in: Experimental Design lesson 2: From a Question to a Testable Hypothesis
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Optional legacy technical materials Open only if you want the original notes, vocabulary, artifact, and CER work
Before this page, you should know
- A question is researchable when it can be answered by collecting and analyzing real, observable (empirical) data; questions of blame, single fate, or value are not.
- PICO sharpens a vague question into Population, Intervention or exposure, Comparison, and Outcome.
If not, review
Today's new idea is only
A hypothesis is a falsifiable prediction, and every experiment must nail down what it changes, what it measures, and what it holds constant.
Goal: Students will write a testable hypothesis and its , and identify the , , controlled variables, and for a study of Mateo's question.
Know by the end
- A hypothesis is a testable, predicted answer to a , and it must be falsifiable (some result could prove it wrong).
- The is what the researcher changes; the is what is measured; controlled variables are held the same across groups.
- A is the comparison that does not get the intervention (or gets the standard one); without it you cannot tell whether the intervention caused the outcome.
- The states no difference or no effect; scientists test the null because you can disprove no difference with data but can never fully prove a positive claim true.
1
A falsifiable hypothesis
Model start: A hypothesis is a testable, falsifiable prediction; there must be a possible result that would prove it wrong.
- A hypothesis is a testable, predicted answer to your ; it must be ____ (falsifiable), so some possible result would prove it wrong.
- Earlier repair reduces speech problems is falsifiable because finding no difference would count against it.
2
Naming the variables
- : the one thing you deliberately change (Study 1: timing of surgery; Study 2: presence or absence of the ____ gene).
- : the outcome you measure. Controlled variables: everything you hold the ____ (same) across groups so it cannot explain your result.
3
Control group and the null
- A is the comparison that did not get the intervention; without it you cannot tell whether your intervention or chance caused the outcome.
- The (H-zero) states no difference; the study checks whether the data are surprising enough to ____ (reject) it. TOPS rejected its null because 8.9% versus 15.0% made no difference hard to believe.
Everything you need for today is on this page. These links are optional.
What to read
Read the short plain-language explanation written for this lesson. Plain-language explainer for this lesson
Why this source matters
This explanation gives you the background for today's idea without making you decode a research paper: A hypothesis is a falsifiable prediction, and every experiment must nail down what it changes, what it measures, and what it holds constant.
Words to unlock first
Reading moves
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Stop point
Stop after the final 'Use it now' section. The research citations are available separately for advanced readers.
Your output
Write one claim-evidence sentence: state the main idea, then name the example or evidence that supports it.
Where this fits
Tested on (Ohio WebXam)
Genetics of Disease · 072130
PLTW lesson
MI · Experimental Design domain · Experimental design, variables, and controls
WebXam domain
Molecular and Genetic Technology
Evidence to produce
Fill in a study-design card for Mateo's surgical-timing question: hypothesis, null hypothesis, independent variable, dependent variable, two controlled variables, and control group; then write one sentence naming the result that would force you to reject your hypothesis.
Lab / skill
Biomedical Innovations (BI) · Principles of Biomedical Science (PBS)
Everything required for today's decision is already in the case file and plain-language explainer. The links below are original papers and database records for teachers and advanced readers, not assigned student reading.
- NEJM. Timing of Primary Surgery for Cleft Palate (TOPS), 2023.
- Gamble C, et al. 2023. Timing of Primary Surgery for Cleft Palate (TOPS trial). N Engl J Med. [PMID:37646677]
- Sun B, et al. 2023. Ezh2-dependent methylation in oral epithelia promotes secondary palatogenesis. Birth Defects Res. [PMID:37435868]
- Claim: The TOPS trial result lets us reject its .
- Evidence: The was ____, and the study measured ____% versus ____%.
- Reasoning: A measured difference is evidence against no difference, because the data are too far apart to be comfortably explained by ____.
How this is graded (rubric)
For: Fill in a study-design card for Mateo's surgical-timing question: hypothesis, null hypothesis, independent variable, dependent variable, two controlled variables, and control group; then write one sentence naming the result that would force you to reject your hypothesis.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in through the route named under Submit here and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
How the model answer scores against this rubric
- CompleteProficient: Nothing is left blank: the model fills every part of "Fill in a study-design card for Mateo's surgical-timing question: hypothesis, null hypothesis, independent variable, dependent variable, two controlled variables, and control group; then write one sentence naming the result that would force you to reject your hypothesis.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be attached to your class form or handed in, and confirmed.
What's next: We can design a single study and predict what would prove us wrong. But two honest studies on the same question can reach opposite answers. Why do scientists trust some study designs more than others?